Postfix vs spammy TLDs

I admit I'm having some trouble figuring out how to get the most of SpamAssassin within amavis-new. However, while working on that, I noticed that something crazy like 70%+ of the spam I'm getting at this domain is from the new-ish .xyz TLD and about 30% of it is from the .link TLD.

Found http://www.linuxquestions.org/questions/linux-server-73/how-to-reject-ad... which got me most of the way. One slight change was required: sudo apt-get install postfix-pcre to get that module which wasn't included in my initial setup.

A little worried about not accepting any email, just in case someone ever hacked my server to send spam I would want to be able to receive abuse reports from those domains, so I left a clue in the error message:

cat /etc/postfix/sender_access_pcre
/\.(xyz|link)$/ REJECT Mail from spammy TLD; if human, try @gmail.com