Not good to be breathing that crap in the basement so I quit.
Back in the day (mid-late 1980's) USAF SP's we use to utilize wax bullets for training indoors in our USAF issued S&W model 15 38 special revolvers (yes some AF bases issued revolvers until the early 1990's)
Basically prime the case and push it down in a block of wax it looked like a wadcutter.
I have done the same thing. As some one above said, you will need to open up the flash hole for the primer to avoid the primer popping out of the pocket. It seems counter intuitive, but the reason primers don't pop out with the much higher pressures of regular cartridges is the case pushes back against the face of the receiver and pushes it back in. If you have one pop out in a revolver it can lock up the cylinder.
I've used them many years ago and they work as advertised. I don't know how accurate they really are at greater distances than 7 yards. I once used one to pop a stray dog. It made him decide that my property wasn't the place to be and it didn't penetrate, so didn't do any damage. As a matter of fact, I found the plastic bullet and used it again, but not on a dog. I think they are best when used for revolver training.Thanks to everyone for the responses! I've heard of the wax but would be afraid of it melting and getting everywhere in the firearm. I'm going to try the Speer plastic in a 38 snub-nose revolver.