I certainly see the lead oxide coat the muzzle with 22LR and lead cast bullets, and if ignored it could be a real a concern.  However, I don't know anyone personally that has actually had this problem.  Lead oxide actually isn't that hard to remove.  Ph and temp are very effective to it's dissolution.  There are a few products that also claim lead oxide removal with out wiping/brushing.  I believe I'm doing fine with the following 22LR application on the 45 Tirant (original model)

1.  After shooting lead, get the can hot shooting jacket centerfire pistol ammo and immediately add vinegar. (drinking water can dissolve lead.... albiet  much slower)
2.  Let the vinegar (mild acid) cool and decant to 1/2 full (the waste has lead nitrate......treat like any poison)
3.  Add baking soda - this will neutralize the pH, but in doing so aggitate the can's internals.
4.  Run boiling water through the can

Perhaps I'm just being a cheap bastard, but from my experience you can shoot lead through sealed cans....just clean it.  I've had a few dealers tell me I'm messing up, but of course they'd love to sell a few more cans too.  Anyone have success or a regrettable experience?

Warning that TiRant45 has aluminum baffles in it. The acid will destroy the aluminum baffles.
A few years ago, I jail broke mine for cleaning.