I have always been afraid to pocket carry with no holster. If there is a reason it just won't work for you I suppose you have no other option. I carry my PM9 in an IWB holster and still find lint accumulating on it. Maybe it is from the leather in the holster? Maybe my shirt??? I dunno for sure, but it does happen. I try to remember to remove the slide and wipe it down about once a week with one those "Remcloths" they have some kind of oil or something on them. It might even be dust accumulation... I don't think it would cause my weapon to jam... it never seems that thick.
I like the dust off idea. I'm going to steal that one and allow my friends to think I thought of it by myself. 