Are we talking about the in tank water softener cartridge found on the end of the intake hose? If so, they shouldn't be soaked in bleach or any cleaners - you can sometimes regenerate the softener cartridge using rock salt or kosher salt, but its usually just easier to replace them, they are about $12-50 , send me a PM if you need to know where . They are also only good for about 30 litres, (10 tank fulls) much less than people think . Usually a much better option is to get a proper water filter, or even Brita/BWT cartridge jug