[squid-users] Forget all memorized 404s

Hi folks,

is it possible to tell Squid to forget all memorized 404s?
For example the parents go down for some time and are now back online.
But 404s from the downtime are still in the cache.

Also in above case where all parents are dead is it possible to tell
Squid not to check the parents and not to invalidate cached content?

Cheers, Markus