This may sound like a dumb question, but I really don't have much experience with mailing things except for large packages and small letters. Lets say I'm just mailing back an atomizer or a battery or something, something small, but something that shouldn't be crushed either, what's the best way to ship it back? Should I just stuff it with some bubble wrap in an envelope, put a few stamps on and mail away? Will it get run through a sorter machine? Should I purchase a special bag or something? Should I pay more for Priority or first class mail?