Given the rules at WheresGeorge.Com about Cache Dollars, I just simply swap out a dollar I find in a cache with another WGD. I then log the one I find at wheresgeorge.com and spend it. This way I get to track the Dollars I find and even get to track some of the Dollars I place in Caches that I have first logged with wheresgeorge.com. It is all part of the GeoCache experience.