Do be careful putting coins in your ashtray.
Spirited driving (or just having to slam on your brakes due to an idiot in front of you) may cause coins to be moved from the ashtray to inside the center console, and some have been found lodged in the shift linkage, keeping the driver from being able to shift into a particular gear fully.
I keep change in mine, and have not had any stray into the console as of yet, but did find some on the floor, thank goodness.