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Thanks to COVID lockdowns, things are shut and I'm anyways miles away from larger market areas. What I do have is litres of sanitizer, the kind that is watery in consistency (not gel-like) and is intended to be sprayed (not squirted).

The composition of(v/v) is as follows :

  1. 80% Ethyl Alcohol
  2. 1.45% Glycerol
  3. 0.125% Hydrogen Peroxide
  4. Purified Water Q.S.

It's flammable and has tonnes of alcohol, basically a good sign as a solvent to dissolve oil and grease, from what I can remember from high school chemistry. Not to mention it also leaves the drivetrain smelling nice ;)

So, is it fine if I use it as usual degreaser (spray, rinse, lube) ?

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  • When I have to get rid of old grease (e.g. when re-greasing a bearing) I just use WD-40. – Michael Nov 13 '20 at 7:45
  • @Michael I have none :( – An Ant Nov 13 '20 at 7:50
  • Do you have any petrol? It is not great and can harm the environment, but degreases efficiently. – Vladimir F Nov 13 '20 at 8:29
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    TBH, with all the fear people have about this, I'm shocked that anyone is willing to use their precious hand sanitizer for anything beyond OCD virus scrubbing. Good on ya! – FreeMan Nov 13 '20 at 17:26
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    If you're in the USA, might want to hold onto that sanitizer for a bit longer... (I'm sure this comment will age well 4 years in the future) – Bryan Boettcher Nov 13 '20 at 18:38
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Degreasers need to dissolve the oils in lubricants. I am not sure why this works from a chemistry perspective, but alcohols like the ones in sanitizer don't seem able to dissolve traditional chain lubricants as effectively as other degreasers, e.g. mineral spirits, turpentine, or citrus degreasers. Indeed, chain waxing proponents recommend that you degrease the chain's existing lubricant using mineral spirits, which are non-alcoholic hydrocarbons, and that you remove the residue of the mineral spirits (or other degreaser) from the chain with alcohol. I have never heard anyone recommend alcohols to remove chain lubricant. It seems that wet lubes are less soluble in alcohol than in the other degreasers mentioned. I am not familiar with chemistry research on how soluble lube is in various solvents, and any comments or answers on that topic would be welcome!

If you are using traditional wet lubricants, I don't think that removing the degreaser remnants with alcohol is needed. This is only needed if you are using paraffin wax. I'm only bringing wax up because this is how I'm familiar with what dissolves what.

NB: After this was posted and accepted as an answer, @llama explained why alcohols are a poor solvent for wet lubes from a chemistry perspective. If you upvoted this answer, please consider upvoting theirs also.

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    Methylated spirits/denatured alcohol is a useful degreaser, and my first choice in many applications, but as you say, it's not a perfect one. – Chris H Nov 13 '20 at 16:20
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    The short chemical answer is that oils/greases are nonpolar, and water and alcohols are generally good polar solvents but not very good nonpolar solvents, whereas the other things you listed are good nonpolar solvents (see also acetone, petrol etc) – llama Nov 13 '20 at 20:25
  • @llama that would be worthy of a separate answer, IMO. – Weiwen Ng Nov 13 '20 at 20:29
  • @WeiwenNg done. – llama Nov 13 '20 at 21:04
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    @llama isn't the ethyl group in alcohols non-polar, and as such alcohol is a good non-polar solver. When I remember right most of the neuro-toxicity of ethanol comes from exactly this property? – gschenk Nov 13 '20 at 23:55
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This might work, but probably not as well as using dish soap and water.

Because greases are made up of nonpolar chemicals, they are best dissolved by either nonpolar solvents or detergents. Nonpolar solvents are fluids made up of nonpolar molecules, which stick directly to the grease molecules they dissolve. This category includes things like acetone, petrol, and mineral spirits. These make good degreasers, especially if they're volatile enough that they will evaporate (otherwise you've just replaced one oily substance with another). WD-40 is in this category.

Polar solvents similarly stick to polar molecules or ions, so that's why you can use water to wash something covered in salt (where it dissociates into Na+ and Cl- ions in solution) but trying to do the same with acetone would be much less effective. This category includes water and alcohols.

Detergents (such as dishwashing liquid or laundry soap) contain chemicals with large molecules having a polar end and a nonpolar end: the polar end sticks to (polar) water molecules and the nonpolar end sticks to the grease molecules, allowing both detergent and grease to be washed away by water. This might be your best bet for common household chemicals, google shows quite a few people reporting good results for using it to clean bike chains.

EDIT: After prompting from gschenk I'm reminded that ethanol is actually a decent solvent for nonpolar molecules as well, due to basically having a polar end and a nonpolar end. Still, as a spray it will just slightly dilute grease. You might be able to use it by putting the chain in a container with it and shaking it around a lot, but you would have to do the same with a detergent, and the other additives in the sanitiser aren't going to do you any favours.

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    Welcome to Bicycles - thank you for an excellent first answer. Keep it up ! – Criggie Nov 13 '20 at 21:33
  • I second that this is an excellent answer because it tells us why alcohol shouldn’t be a good degreaser. However, it raises a question. As I stated, when using hot paraffin wax, standard procedure is degrease the chain, then use alcohol to remove any film from the degreaser. The recommended degreaser is usually mineral spirits, but citrus degreaser will also do. If these are non-polar solvents, then shouldn’t alcohol, being polar, also be a relatively poor solvent? Or is there another mechanism of action at play? – Weiwen Ng Nov 13 '20 at 22:54
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    @WeiwenNg There's 2 possibilities I can think of: one is that the film is caused by contaminants/additives (or just left over polar stuff from dirt, which tends to be sticky) and not the main ingredient of the degreaser. The other is that the degreaser is further up the polarity scale than the grease, so that it mixes with both the grease and the alcohol. – llama Nov 13 '20 at 23:08
  • Thanks for the chemical knowledge ! Appreciate it – An Ant Nov 14 '20 at 1:49
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I don’t think it’s a good idea.

Glycerol attracts and retains moisture (it’s used as a food additive to keep moist food moist).

Hydrogen peroxide is an oxidizer. I think both substances are going to accelerate rust and corrosion.

I’m just surprised there is no acid in it (which again would be bad for metal) to match the skin’s acidic PH value.

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    But it has those in very little proportions and they'll be exposed for a short duration only ... still a horrid idea ? – An Ant Nov 13 '20 at 7:50
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    @AnAnt Consider that water has none of those bad things, and is still a poor degreaser. Adding small amounts of bad ingrediants won't make it any better. But you have lots of sanitiser, so consider a test run on some worn-out or spare chain. Do half with a degreaser, and half with sanitiser, and see which is best. – Criggie Nov 13 '20 at 8:17
  • As for why it doesn't have any acid to balance hand pH : as stated, it is a spraying sanitizer , closer to an alcohol wipe than a hand sanitizer . – An Ant Nov 13 '20 at 15:46

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