What do i do with old radiator? i have one of those old fashioned central heating radiators.?

If the paint is only 20 years old, it is unlikely that it is toxic.

You can get a lead test stick from any home improvement center. Just rub it on the paint and it will show if it contains lead.

A paint sprayer might help, though you do need to clean thoroughly first.

There should be a nut somewhere on the rads. I have not got a key but we loosen them with a pliers to bleed them when they need it. Its just air comes out , when it stops hissing they are bled just tighten them back up again. Its easy. I don't know if that would cause the banging noise in the attic though. Probably an air block there. We usually deal with that by just banging on the pipe up there with a hammer . Probably all wrong advice lol but it works in my house

it probably wont bother you unless you lick the rad. clean as best you can w/ that narrow attachment on your vac, and use a wire brush for boiler cleaning on the rest. mask off w/paper and spray w/ a high temp spray paint, available at auto parts store

If you don't want to bring it to a salvage yard, then take it apart and clean and paint it.