RE: Cox .049 issue
as long as you have removed all plastic parts and gaskets (ie: only the cylinder and piston/rod in the oven) then you should be good for 200-300 F. You could probably go more, but its unnecessary. Castor will go soft in boiling water at 212F. But just because the castor is soft, doesn't mean the piston will give up without a fight. But it helps.