As it is not in the cards right now to reline the tank, I flushed and vacuumed it out.
His petcocks are missing screens and the straws have been cut short. I went through my parts stash and am putting together some acceptable petcocks for him, with the missing screens and correct length straws.
In going through this, I discovered that our Karcoma petcocks have a secondary screen inside the outfeed fitting. I just thought that many may not know this....and should. Add this screen to your annual tank flushing routine.