I usually only look for pre-71 halves. Should I be looking for other halves that have silver in them (i.e. proofs)? How do I know if it is a proof? Are they all minted in San Fransisco?
1987p 1987d 2002+ 1970 and prior, all s mint coins(proofs) you will know because they are super shiny. Also anything that catches your eye that you want to keep(foreign, painted halves, magicians coins, etc)