I'd just throw em all in together. Even just in with your other loads of clothes. Unless you want to do your prewashes without any detergent at all, since they're not dirty.

When you say 'the outsides not being fluffy', are you talking like covers or the shells of pockets? Because they won't need the prewashes that absorbent materials like bamboo/hemp does. You could just wash them once to get any manufacturing residue out.