i read somewhere a while back that one must be more careful with a 22LR can or 5.56 can shooting 22LR in it as the lead builds up and can cause issues.
is cleaning it with an ultrasonic cleaner sufficient to avoid any issues like this?
thanks

Apparently the leads vaporizes in the can causing build up. I was told to use "Krol" or WD40 overnight in a can, then drain it and blow it out in the morning.

Most centerfire cans are made out of SS or highly corrosion resistant metals so soaking them in a 50/50 mix of vinegar and hydrogen peroxide will dissolve the lead out without harming the can. It can dissolve aluminum though.

If you do this do not get any on your skin. The lead becomes water soluble when it dissolves and forms lead acetate.

Along similiar lines but a different technique.
I cast my own bullets and have a smelting pot. If I were to dunk a leaded up can into a full pot and let it set until up to temp then pour the molten lead/slag out.
Would that work, would it destroy and aluminum/stainless steel can?

i would NOT do that, as lead melts at 600 F+ and that can affect the temper of the material.

i have a ultra sonic cleaner, will that zap the lead and not have to wory about leadsulphite(IE liquid based lead by using the peroxide cleaning method?) I do have a SS 5.56 suppressor that will be used with a 22 pistol as well as the AR's.
and eventually a 9mm can that will be used with cast bullets through a 2XTM