Let a good welding shop change the valves. Ive never done it either,Ive always used new bottles. Or try calling the company with the bottle or valve you want to use. You should be able to paint the bottles,Ive sure seen it done!! As far as new stickers, You dont have to have stickers on the bottles if you dont want them, The recert info is stamped into the bottles when there made and arent on the stickers!!! Hope this helps,David.