Unfortunately, you are using an out of date browser which is not fully compatible. It may not display this or other websites correctly. You should upgrade or use an alternative browser.
My old boss, the infamous Kramer the Framer, used to write customer names, order numbers and pertinent info on the backs of stuff, in ballpoint. I open up old frames and see the same written in pencil.
I can never remember the ref numbers so I often do little thumbnail doodles on invoices or write a brief description which usually gives me some sort of clue .
When I frame stuff that already has a mat on it I sometimes get the urge to write something like -
"I didn't cut this mat. Not my fault. It was like this when I got it. Honest".