Like Hoard....when I was out in CA, I used to get the ones stamped with RC regularly (1 or 2 per week). I was fooled just once with a half that looked like silver and it said "no" on it.
I've marked halves over the years, but not so much now. When I did mark them, I did two for every $10 roll. I usually marked them with the initials of the out-of-town city that I was going to dump them in and always with a different colored marker for each out-of-town city.

Almost all of the cities were at least 1.5 hours away from the home city (wherever I was at the time). In most cases, I dumped large amounts (ie $4000 or more) to make it worth it. The good news was that I never did get any of my original halves back.