Football

I don't collect stamps. Funnily enough though I do collect urine samples in jars marked by what I have eaten and drunk in the previous 24 hours, as well as well as retired dutch defenders.

The trick is to take two samples and store one in the fridge while the other is left in sunlight, compare again after a few weeks to see how they now differ. There's probably some boffin on here that will tell you why one will no longer have the same piquancy as the other.