Bottle cap collecting is the hobby of collecting metallic crown caps. The hobby may or may not include drinking beverages that have been sealed with crown caps. Opening bottles with traditional openers may damage the crown caps, thus some collectors use automatic bottle openers to avoid any substantial damage to the crown caps.[1]
Pol Høegh Poulsen is the record holder, having the largest collection in the world with over 101,700 bottle caps.[2]
There is also a record for longest line of bottle caps, which is 87,575 bottle caps.
In the video game series Fallout, bottlecaps are collected and used as a form of currency.[3]