Pellet lube

Dish soap and hot water works great and I use Napier power pellet lube. Comes in a spray bottle and can lube a dozen or more tins per bottle. I wash a tin dry them and put them in a gallon ziplock baggie to spray them, then back to the tin. I keep using the same baggie over and over. Besides keeping the barrel clean longer I believe it helps the breach O Rings last longer.
 
I squirt a good amount of 3in1 brand Silicone oil in a pellet tin with foam in the bottom. Then I just dump a few dozen slugs in at a time while shooting, and roll them around on the foam to coat them. This wet lube works well while bench shooting. Running a dozen of them dry doesn't seem to effect much as far so accuracy and lead buildup goes. When I put wet slugs in there afterwards it seems to clean things up.