Objects used for rests/ashtrays

[mobarbq]

I'm curious as to what various objects the inmates might use for cigar rests or ashtrays, which are not commercial in nature.
As an example, I often use a little item I picked up a couple of years ago when I visited Union Pacific Steam Locomotive #844. The brakeman told me this was a piece of brake lining from #844, just a chunk that fell off. It makes a cool cigar rest. I'm a train fan as well, so it fits right in.

What else are you guys using? Thanks.

http://qsl.net/kg0yh/upbrake.jpg