Cleaning older rock

[mseepman]

So I am starting a new Nano tank with my daughter as she really wants to try helping me with a tank and my big tank has more problems than I want to tackle with her. I will do a tank thread on it shortly.

I have some rock that I took out of my refugium on the big tank that I think had some green turf algae and a little bit of bryopsis. This rock sat outside in a bucket in the sun and the cold for the last year. I took it out in frustration and I guess I was "punishing it" lol. Anyways, I've been soaking it in RODI water for the last week and I notice it has a lot of dead algae on it still. I know this crap can come roaring back unless I prepare the rock but I'm undecided as to how to do this.

Can you give me some ideas that you have done yourself in the past. I know that acid is an option but I'm not super excited to do that in the winter and snow.