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Softening rubber

Softening rubber with methyl salicylate aka oil of wintergreen

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This is just a quick note on this - a proper writeup with photos will be coming eventually but enough people ask me this that I am putting this up in the meantime. You can get oil of wintergreen on eBay US, eBay UK, eBay AU or Amazon.

Note that methyl salicylate can be fatal to children in doses as little as 4ml - so if you are doing this at home where children might get hold of the stuff... well, just make sure that they don't. See the Wiki page on methyl salicylate for a little bit more info on that.

Oh, and one other note - I use a little portable hot plate and do this out in the workshop as it the odour may not be appealing to any other people you live with... I also use a cheap pot bought for the purpose so I don't have to worry about cleaning one that's used for food purposes.

From Murray of Murray's Carbs - and this is a recipe I have personally used with success - for softening rubber with oil of wintergreen;

You need a stove and a pot sufficient to hold the parts. Not too large or else you'll end up using a lot of water to cover the parts.
Cover the parts with water and one teaspoon of oil of wintergreen. If it's more than 10oz (300ml) of water add a second tea spoon of the oil.
Boil the parts for 4-6 minutes and then leave the parts in until the water cools, then remove.

Here's how to soften rubber parts using methyl salicylate, also known as oil of wintergreen.

This works well for carburetor insulators (also known as the intake manifolds) on motorbikes - it makes them a lot easier to reinstall if they are old and hard. It may well reveal cracks you didn't notice before doing it. I have also used it to rejuvenate old rubber gaskets where no replacement was readily available, though I can't comment on gasket longevity if you do that.