I use an overball lube of white Crisco cooking lard (grocery store), filling the front of each chamber even with the cylinder face. (It's available in both small/large canisters)
The heat of firing melts the lube and keeps powder fouling very solft/sloppy, so that shooting can continue as long as you wish.
Often, I stop for a minute or so, to simply wipe the excess slop from the grips/hammer, etc - so the gun doesn't slip in my hand during firing. .
Yep, It's messy - but it works.