At nappy change, take off the nappy and wrap and seal the Velcro tabs over on themselves and drop into the nappy bucket.
When you have enough nappies, boosters, washable liners and wraps for a load place them in the washing machine on a warm wash.
Best results are achieved by using half the manufacturers recommended amount of a non-bio detergent or less.
Friendlier detergents such as Ecover don't contain optical brighteners so staining might be visible but all's not lost as drying the nappies in direct sunlight will make 99% of staining vanish.