Some people want to use something that other people do not want to use any longer.
That is why we exchange things, sometimes with money.
For something utterly valueless to someone, other people pay a hefty sum of money.
Would you believe that some people pay 50 to 100 dollars for your used underwear. The dirtier, the better.
Some people collect stamps, tin toys, or small figures of soldiers of Napoleonic era.
To them, authenticity is very important.
It is the same to our collectors of your dirty undergarments which have spent days and weeks at the bottom of your backpack.
You need to prove that you are the one who is responsible for the sacred stains. You will be gently asked to pose for a photo session. You don't have to undress completely. You just have to show that the object has been attached to your body.
Luckily or unluckily, boys cannot sell theirs.
However, this is a kind of information you should remember when you are in need of money in Tokyo.
It might be worth convincing your female travel companion to contribute hers to the collectors of the unusual objects.
I haven't finished the article yet, but it will be posted to Asakusa Underground in a few weeks' time when Mon Chi-chi is back from Thailand.