For two cars that are ~$3500 each, I would probably consider dropping the C&C on them, assuming that I had enough in savings to cover the loss. Depending on what your deductible is you could be paying $1000-2000 anyway should something happen to both of them at the same time.
Personally, I keep C&C on the nicer of my two paid-off cars, but it's only 6 years old (and I've only had it a month). It saved my ass a few months ago when the last one got totaled in a wreck. Insurance paid to replace it with the same car, down to the same color, with an upgraded trim package and lots fewer miles.