I use OxiClean oxygen bleach. As I understand it, all the powdered oxygen bleaches dissolve to form hydrogen peroxide and soda ash. OxiClean has no fragrance or optical brighteners. A big box at Costco is cheap.

I'm pretty sure Ecover is one of the only brands available that is 100% sodium percarbonate, with no added washing soda "filler."

Chemistry store sells sodium percarbonate in 2 pound jars (and larger quantities, too) but their shipping costs tend to be a bit on the high side.

Here is a link that might be useful: Chemistrystore.com

I've ordered from this website before without problems, I think I'm going to try oxiclean now and see if there is a big difference since it's cheaper the sodiumpercarbonate. They offer free shipping...

Here is a link that might be useful: sodium percarbonate

PEOPLE - DO NOT BUY OXYCLEAN! Oxyclean is only 50% or less sodium percarbonate. The reason OxyClean seems "cheap" is because it only has half the active ingredient of other products. When you buy pure sodium percarbonate, you are getting 100% of the active ingredient. OxyClean is full of fillers. You will need to use half as much sodium percarbonate to get the same effects as OxyClean.

Sodium percarbonate is also excellent at killing mold-based plant diseases. Dissolve about 3 tablespoons of pure sodium percarbonate in 1 gallon of water and spray onto the affected plant and soil.