Trying a aggressive approach. This piece was completely covered with RTA. Used a cordless drill with a wire brush:
Rinse with tank water and placed back into tank:
These two pieces were treated with 35% peroxide a few weeks ago but it appears that something's coming back:
Rinse with tank water and placed back into tank:
These two pieces were treated with 35% peroxide a few weeks ago but it appears that something's coming back: