I've heard that a variety of chemicals collectively called "Antichlors" are used to remove excess bleach from textiles and paper pulp after beaching them, but that's about all I know about the stuff.

This web site:
Antichlor - Wikipedia, the free encyclopedia

says that sodium metabisulfite can be used as an antichlor. Sodium metabisulfite can be purchased in any beer and wine making shop. It's dissolved in water and used to sterilize the beer or wine making equipement.



Sodium metabisufite is used to sterilize beer and wine making equipment because the sulphur dioxide gas it releases will kill bacteria, but isn't poisonous to us. In fact, sodium metabisulfite is used as a food additive, but I don't know how it's used in food.