I use to spend hours cleaning my aquarium plants, rocks, filters, etc till the guy at the fish store told me his solution. Bleach. Needless to say I thought he was kidding. He was not kidding and he was right. His point was rocks and plastic are not sponges. They will not soak up the bleach. As long as you rinse well, it is fine. My routine now is to scrub the glass with a glass scouring pad. Then I take out all the plants and rocks that are covered in algae. These all go into my kitchen sink which I fill with hot water and a cup of chlorine bleach. I leave them to soak while I get back to the tank. Then I vacuum the gravel and take out about 1/3 of the water. Change the filters and start refilling the tank. Then I go back to the sink to check the plants and rocks. They all look brand new. Rinse in clean cold water, soak in clean water for about another 30 minutes. Then I dry the plants off to get rid of any possible water sticking to them and stick them back in the tank. If you are worried, test the water for chlorine once the plants and rocks are back in.