I followed the directions provided, but it did not come as clean as I had hope:

Stimulite® honeycomb can be hand laundered or machine washed in cold water, using a gentle cycle. If your Stimulite honeycomb product includes a cover, wash the honeycomb and cover separately. Use only a small amount (~1 TBSP) of mild detergent. DO NOT USE CHLORINE BLEACH. After washing, shake the honeycomb to remove excess water and then either let it air dry or tumble dry on low heat in the dryer. Do not dry honeycomb with wet clothes as this causes heat retention which can damage the honeycomb.

All Stimulite cushions and support surfaces come with their own mesh laundry bag for machine washing and drying.

*Use front load washers only as agitator can damage honeycomb