I think that the problem with shredded stuff is that it can contain bits of staple, bits of plastic, shredded credit cards and computer discs as modern shredders will do the lot...it's therefore not saleable as waste for recycling.
Agree with ummmm. Add very little detergent to warm water, and swish around occasionally. The print will all blur, and clumps will dry out stuck to each other.
Telly on - two bin bags - just tear up into smallish bits whilst enjoying cuppa and telly and as you go put handfuls of same document either side of you into different bags.