title_body: Where can I found out which beer cans are "collectable"?
upvoted_answer: Breweriana has a database of collectable beer paraphernalia with prices.  Tick the "include All (In-Stock &amp; Sold)" button for their complete range.  They're trying to sell to you, of course, so their prices are probably a bit higher than you'd getting selling the same thing, but it's useful if you have an item you want to get valued.
  
  Ebay, on the other hand, is more limited but more practical.  It's a good first stop for selling any collectable, since you can see what people have actually gotten for items.  That'll be the most accurate price estimate, although you're not likely to find really rare stuff on there because of the small audience.
  
  Also, there are a number of books on the subject, of which breweriana helpfully lists a few.
  
  Finally, the BCCA is the largest organization around beer can collecting, and have a lot of resource son the subject.  You can use their site to find a local chapter and ask someone about your specific collection in person.
  
  
  
  To expand on this a little, here is a really quick guide:
  
  
  If it's from the mid 70s or so on, it's probably not that valuable.  Exceptions sometimes include aluminum cans, cans with punch tops, and cans with cone tops.
  If it's in poor condition, it's probably not worth much unless it's quite rare.  Unless it's better than "grade 2" (defined as "Has a clean label, but there may be rust or other blemishes near the seam, the lid, or the bottom. Colors may be irregular"), it's probably not valuable.
  American OIs (opening instructions, named after the instructions that came with them on how to open them) can be worth $35 to $1000.  Most others before the 70s will have a chance of being between $10 and $500, depending on their rarity.