Of course, this post is a pun. It plays on the phonetic similarity between the words cash and cache. Cash is a form of currency, often metal coins or paper bills with an attached artificial value. Cache is a term used in computing and is a type of memory. Cache is also a collection of items of the same type stored in a hidden or inaccessible place. If we assumed OP had it stored in either, this would effectively result in a double pun.