You’re standing in the store aisle looking at three bottles: 70%, 91%, and 99% isopropyl alcohol. They all say “isopropyl,” but when it comes to ripping thick resin out of a dirty bong, they do not perform the same.
For disinfecting wounds or surfaces, 70% is the perfect option. But bong resin is a sticky, oily, non-polar mess or organic and in-organic molecules that don't care about hospital protocols. In our world, water content is the enemy. The higher the purity you have (91% or 99% isopropyl), the more raw cleaning power you’re throwing at that resin—and thus it breaks them down much more readily.
In this guide, we’ll walk through why higher concentration iso works better for our purpose, what’s actually happening at the molecular level, and how 70%, 91%, and 99% compare in real-world cleaning scenarios.
Table of Content
The Power of 70% compared to 99% Iso
What You’ll Need to Do the Test
To actually put this into practice, you don’t need much:
70% isopropyl alcohol (baseline / comparison)
91% isopropyl alcohol (a bit stronger, common middle ground)
99% isopropyl alcohol (maximum solvent power)
Caps or plugs (Hytek Caps or similar) to seal joints for shaking
Coarse salt or cleaning media (optional, for extra abrasion)
Warm water for rinsing after
- Gloves + ventilation (iso is drying and flammable)
- We also used a StemClenz Kit and an Original Pipe Perfect Brush Pack, which are suggested but not required.
Pros of 99%
Extremely effective solvent – Dissolves sticky oils, waxes, and buildup quickly with minimal effort
Fast-acting – Cuts through residue in seconds rather than minutes
No residue left behind – Evaporates cleanly without streaks or films
Versatile – Works on glass, metal, ceramic, and many hard surfaces
Disinfecting properties – Helps reduce bacteria and unwanted odors
Cons of 99%
Flammable – Requires careful handling and storage away from heat or flames
Not safe for all materials – May damage plastics, rubber, finishes, or painted surfaces
No surfactants – Loosens residue but doesn’t “lift and carry” debris like some formulated cleaners
Must Have Products For the Clean Crew
Why Water Content Matters
Resin Is Non-Polar, Water Is Polar
Bong resin is mostly non-polar organic gunk: tar, oxidized oils, cannabinoids, and waxy residues. Water is polar, which makes it great for dissolving salts and sugars—but not great at dissolving oils and resins.
Isopropyl alcohol (IPA) is an organic solvent that dissolves oils and natural resins extremely well, which is why it’s widely used industrially to remove oils, gums, and resins.
When you add more water to the bottle (like in 70% iso), you’re literally diluting the part that actually dissolves resin and adding more of the thing resin hates.
What’s Actually in 70%, 91%, and 99%?
70% iso → 70% isopropanol, 30% water
91% iso → 91% isopropanol, 9% water (near the azeotrope)
99% iso → ~99% isopropanol, <1% water
Further Readings
→ Shake to Shine Vs. Simple Soak: Which Cleaning Method is Best for You?
→ The Best Bong Cleaner & How to Clean Your Bong: A Professional Guide
For bong cleaning, the only thing you really care about is: “How much of this liquid can actually attack resin?” And that’s where higher percentages win.
Why Higher Concentration Cleans Faster
1. More Alcohol Molecules Doing the Work
The main job of isopropyl alcohol inside a dirty bong is to act as a solvent for sticky, oil-based resin buildup—something water alone can’t do.
In 99% iso, nearly every molecule is isopropanol, so almost the entire liquid is engaged in dissolving resin.
In 70% iso, 30% of the bottle is water, which mostly just dilutes the solvent power.
More alcohol molecules = more contact with resin = faster and more complete dissolving.
Solutions and Tools for Puffco and Quartz
Faster, More Efficient Cleaning
With 99% isopropyl alcohol (and, to a lesser extent, 91%):
Resin softens and dissolves rapidly instead of slowly loosening
Significantly less soaking time is required
Many cleans can be completed in a single soak-and-shake cycle
Lower concentrations like 70% can still work, but they behave more like a diluted solvent in a water bath. The added water reduces solvent strength, which often means:
Longer soaking times
More aggressive shaking or abrasion
Multiple cleaning rounds to achieve the same result
This is why precision applications—such as electronics and lab cleaning—consistently recommend 99% isopropyl alcohol for removing sticky, non-polar residues. When efficiency matters, 99% delivers the fastest and most complete clean.
Cleaner, Faster Evaporation
After cleaning, the goal is a surface that’s truly reset:
No greasy feel
No streaks or water spots
No lingering moisture trapped in chambers or percs
Higher-concentration isopropyl alcohol— especially 99%—evaporates faster and more completely because there’s far less water in the solution.
99% isopropyl alcohol → almost entirely volatile solvent → rapid drying with minimal residue
70% isopropyl alcohol → nearly one-third water → slower evaporation, more moisture left behind, and a higher chance of spotting or film if not thoroughly rinsed
For glass and precision instruments, chemical suppliers and laboratory cleaning guides consistently recommend 91–99% isopropyl alcohol for this reason: it cleans thoroughly, dries quickly, and leaves surfaces genuinely residue-free.
Further Readings
→ Shake to Shine Vs. Simple Soak: Which Cleaning Method is Best for You?
→ The Best Bong Cleaner & How to Clean Your Bong: A Professional Guide
Head-to-Head: 70% vs 91% vs 99% Isopropyl Alcohol
70% Isopropyl Alcohol
What it’s actually optimized for:
Surface disinfection and skin antisepsis—where added water helps slow evaporation and improve microbial contact time.
When used on heavy resin buildup:
Limited solvent strength against oily, non-polar residue
Tends to loosen buildup rather than fully dissolve it
Often requires long soaks, aggressive shaking, and mechanical help
Leaves more moisture behind, which can contribute to streaking or lingering film
Verdict:
Works for light maintenance, but struggles to fully reset glass. Residue left behind can harden over time.
91% Isopropyl Alcohol
What it improves:
Stronger solvent action than 70%
Faster evaporation
Better performance where water interference matters
When used on resin:
Dissolves buildup noticeably faster than 70%
Requires less soaking and agitation
Effective for routine cleaning if done consistently
Verdict:
A solid middle ground, but may still leave trace film on heavier or aged buildup.
99% Isopropyl Alcohol
What sets it apart:
Nearly pure isopropanol, delivering maximum solvent strength with minimal water dilution.
When used on resin:
Most effective at dissolving oily, polymerized residue
Penetrates and breaks down buildup instead of smearing it
Often works in a single soak-and-shake cycle
Evaporates rapidly and cleanly, leaving glass truly residue-free
Verdict:
Fastest, most thorough option. If the goal is restoring glass to a like-new condition, 99% is the clear winner between the three.
Practical Cleaning Scenarios
Light Film or Tinting
70% → Works, but slow and often leaves residue
91% → Faster and cleaner
99% → Usually done in one short session
Heavy, Baked-On Buildup
70% → Multiple rounds, heavy agitation, inconsistent results
91% → Effective with time and effort
99% → Softens and dissolves buildup fastest; best chance of a true one-and-done deep clean
Bottom line:
Lower concentrations can clean eventually, but 99% cleans completely. Using a stronger solvent periodically prevents invisible film, long-term buildup, and the need for aggressive scrubbing later.
The Author: Sam Claytor
Sam is the President of Hygenix, a company specializing in premium cleaning and preservation products for enthusiasts and everyday users. With a keen focus on science-backed formulas and customer-centric design, Sam leads Hygenix in creating solutions that combine high performance with practical convenience. His leadership drives innovation in product development, brand strategy, and market expansion.
Frequently Asked Questions
Should I use 99% Iso for all my cleaning?
For cleaning concentrates 99% isopropyl will be the best tool for the job. If you are cleaning bongs and pipes, Shake to Shine and Simple Soak would provide a much improved experience over 99% alone.
Why do we use 99% Isopropyl?
From a chemical and materials-science standpoint, 99% isopropyl alcohol is used because it directly targets the oily, waxy, and partially polymerized residues left behind through a close match in polarity. These residues are largely hydrophobic, meaning water is ineffective, while high-purity IPA can dissolve them at a molecular level rather than relying on abrasion. The higher concentration minimizes water content, maximizing solvent strength, improving penetration into hardened buildup, and preventing smearing or streaking. At 99%, isopropyl alcohol evaporates rapidly, leaves no residue, and does not react with glass or metal, making it an efficient, repeatable, and clean-evaporating solution for precision cleaning.
Can I use 70%?
Yes, you can use 70% isopropyl alcohol, but it’s best viewed as maintenance cleaning, not a complete solution. The higher water content limits its ability to dissolve heavier, oily buildup, so small amounts of residue are often left behind. If you notice a film on the glass once it has fully dried, that film is leftover buildup that wasn’t fully removed. Over time, this residue can harden and layer, eventually becoming the kind of buildup that 70% alcohol can no longer remove on its own. Periodically using stronger cleaners fully dissolves and resets those deposits, preventing long-term accumulation, improving performance, and reducing the need for aggressive scrubbing. Ideally, the goal is to restore glass to a like-new condition—not just make it look clean.
Does 99% Isopropyl dry out your hands
Yes, 99% isopropyl alcohol can dry out your hands, but for most people it’s not severe with occasional use. Because it evaporates so quickly, it pulls moisture from the skin, which can leave hands feeling dry or tight after repeated contact. If you have sensitive skin or are cleaning frequently, wearing gloves is an easy solution and completely prevents irritation. A quick rinse and moisturizer afterward also keeps skin comfortable while still getting the benefits of a stronger cleaner.
