How can I selectively clear the cache for Sinatra + Nginx + Phusion Passenger?

Question

I have a modular Sinatra app running on nginx with Phusion Passenger. When I alter my app (and in particular, some YAML files which are used to generate pages), I'd like to be able to clear only the parts of my cache that are affected (and leave evertyhing else in /public alone--I know I can just clean out the whole cache, but I was hoping not to).

Thanks!