You can soak them to make them SEEM hotter, or you can add a liquid which is hotter. I do not believe you can soak them in anything else which will make them hotter. Soaking them in fluids in general, and then consuming them, will give the cap a carrier that will more evenly distribute it through the entire mouth. Distribution can cause the perception that it is hotter. You can also add a liquid like 'pure cap' or similar. Soaking them in that would certainly cause them to be hotter but not in the same way I believe you are asking about. Hope this helps! -Jim Campbell MWPH