[squid-users] not caching a mime type

what is the best way of expiring existing entries of a certain mime type
and not caching them anymore?

Is this enough?
refresh_pattern application/ocsp-response 0 0% 0

I tried this too
acl ocsp-response rep_mime_type application/ocsp-response
cache deny ocsp-response
but requests of this mime type still get cached.

How do I go about doing this?
thank you.