It would seem to me, that the "safest" thing to use (and what OSS shows) is a gun specific solvent. Which one would work best, I have no idea. Hoppes Benchrest? Butches Bore Shine? Slip 2000 Carbon Cutter?

I like the idea of weighing your brand new can - very, very much, thank you. This would also tell you if your chosen method is working. I worry about internal damage due to the chemical used - especially non-gun marketed chemicals.

Thanks for the thread! (Rugged Razor in jail).

It's a lot easier to build a serviceable can at pistol pressures. I am sure you could build a serviceable rifle can as quiet as a sealed one but it would be a lot heavier so nobody would want it.