The Potassium Permagnate leaves a coloured residue but is ignored anyway (or can be explained by the phenomenon, or even as match or matchbook residue). If you were to put both chemicals in a test tube and sealed it with a cork, you would get a very explosive reaction. it is necessary to keep it in an open container such as a glass so that there is only combustion.
As for holding it, first of all, why on earth would you even consider holding such volotile chemicals in your hand knowing the reactions that are caused with them. You would run a huge risk of being severaly hurt. Secondly and more importantly, the effect is that it occurs away from you and that you apparently cause it to happen without "doing anything".
Paul Alberstat http://www.stores.ebay.ca/abstagecraft