A way to force-dump all permissions given by your av?

Is there any? For example, any item you give anim permissions to keeps them *indefinitely*, unless deleted or reset. Which means there's a huge potential for abuse and you can't really trust anything.

Same with sitting, since it also gives anim perms.

Nope. If you want this ability, go to Jira and vote for VWR-2326. You may also be interested in VWR-1750.

Voted. I can't believe the Lindens would NOT have this already, though.

As I said in the thread on the JIRA: Very important that this is implemented. There's already abuse in-world with (invisible) sitting objects that keep the perms and keep playing animations on you against your will. Teleporting away isn't much help if it happens in a sim you have business in.