I also agree, don't know what condition your guns are in or how you go about normal cleaning, but I have found a light cleaning every 10 to 15 rds and a thorough scrubbing every 50 rds or so and have not had any problems with fouling build up. There are many products on the market but for the deep cleaning I like Blue Wonder cleaning gel, and for the lighter cleaning in the field or at the range I use a bore snake and then Hoppes when I get it home.