[ricard]

There is an excellent cleaning spray for rubber form Teslanol, called GR (Gummi Reiniger). It's extermely fast drying. According to the material data sheet one of the main components is IPA, but there are also other hydrocarbons in the mix. (I don't personally spray it directly on rubber surfaces, I spray it on a rag and use the rag to clean the rubber).

I'm certainly no chemist, but it would seem to me that the faster the solvent evaporates, the less chance of it taking softeners etc from the rubber, as opposed to a solvent which evaporates slowly and therefore has time to dissolve whatever additives there are to keep the rubber supple.

I remember once someone recommending not to use meths for cleaning pinch rollers because it dried them out. Meths, at least the variety I can get hold of, leaves a residue, so that would be the main reason not to use it, but also it certainly evaporates slower than IPA, so I've been assuming the rate of evaporation plays an important role.