I have a jacket of waxed cotton which has got (dirty) bicycle lubricant on it from a bicycle chain. Unfortunately, I don't know the exact composition of the lubricant because the bike isn't mine. However, the oil/grease was somewhat "wet" (i.e. not very viscous) and very dark (i.e. it holds dirt very well). How can I remove the grease stain without ruining the material itself?-- According to the manufacturer's website, the way to "clean" the jacket is to use cold water and a sponge. Likewise, another website warns in much stronger language to adhere to this cleaning regimen lest the jacket be permanently damaged. I have already tried using cold water and my fingers to try to "sponge" away the grease and then later using an actual sponge, but it is already stuck on too firmly for that to work. I also tried a copious amount of saliva and more hand-rubbing, but this didn't work either.
You could try leaving salt or some other absorbent grainy material in contact with it. This would ideally absorb the oil. As the jacket is waxed, the oil shouldn't be penetrating the material at all so it should just 'wipe off'.
You can try applying talcum powder/french chalk - it's lipophilic, combines with the oil or grease and can be brushed off.
If the lubricant stain has hardened, you may need to soften it first with a hair dryer, or by working in a tiny amount of paraffin wax.
Then sprinkle the area liberally with talc and work it in with your fingers. Leave it for an hour ot two, and then brush it off with a stiff clothes brush. It may take a few applications, or leaving it on for longer - you'll have to experiment. Finally sponge it over with cold water and rewax when dry if needed.
I prefer, you better go for dry cleaning services. On passing through all these comments and clarifications, I get that it will be some sort of stain. So to remove that, you better approach dry cleaning centers near you. But the service may be costlier. So you first decide on whether that bag is of much importance to you, that you have to get it dry cleaned after paying much.
I am also attaching a link for you to do the dry cleaning at your home itself. May be, it may be tedious for you. Any way, if you approach such a center, cleaners will be able to tell you whether that stain is removable or not. They may also tell, how much they can remove.
So you decide upon that. Since, most of them are using powerful chemical agents for cleaning depending upon the material, you do not have to worry about material in that case.