Sockets are the best, Ive used hundreds in my life lol.

The danger in smoking out of aluminum foil has nothing to do with residues being burnt off, it produces no extra smoke, unless the foil has some extra layer of some sort which is rare. What does happen is when aluminum is heated, it realeses ions, so you are breathing ionized air, or O^3 better known as Ozone. The damage is not immediate, it is a long term, lung and throat cell mutating process.

And no, Tin is not a safer alternative.

I have smoked out of countless hundreds, possibly thousands of aluminum foil bowls, and Im still fine, but I know what Im doing to myself lol. Incidently, those Ionic Breezes that filter air so effectively release much more ozone than smoking out of aluminum foil, which I find humorous.