Originally Posted by
sethweinstein
Anything left over from 70-plus countries, even currencies no longer in use. Last year I eschewed my old bag-of-everything in favor of country-specific 6.5"-by-3.5" envelopes. Obsolete money is a nice souvenir. In-use money goes in its envelope with transit cards, so when I head to Hong Kong I just pull that sleeve and I've got cash and my Octopus card.
Not as tidy, but I have a hobby of collecting Starbucks mugs from cities around the world. Leftover currency and transit cards end up in the mugs in case I need them for a subsequent trip. I'm up to about 75 mugs around the house at this point. Any small trinkets/souvenirs (basically limiting myself to things that fit in the mug) also are stored there. The only challenge is remembering that Euros always go in the Paris mug (not sure how it got designated) and leftover currency from countries I have yet to get the mug end up in adjacent mugs (i.e., Uruguayan Pesos in the Buenos Aires mug).