I was just using some art materials for a project, that have been with me for a remarkably long time. There are the german white hot glue sticks (Schmelzkleber) that have been waiting to become useful for many years. The price- twice reduced, which is probably why I bought them in the first place- is in DM, Deutsche Mark, pre-Euro, but I think they are even older than that, ca. 1996, before I moved to the US. I'll show you the perfect use I found for them very soon!
And then there are these Rowney acrylic paints, big old bottles that I bought when I was living in England, also around that time. They are in amazingly good shape for their age and I use them all the time. The best thing about them is that they smell really good and often the smell reminds me of my time in England, the way only smells can take you back.
They were amongst only a few prized possessions that were chosen to come across the atlantic with me.