Can the mask be washed?
It is recommended that you wash the neoprene shell of the mask every month under normal use. To do this it is necessary to remove the filter and the valve first. Although spare valves and filters are available from your retailer, please be careful not to misplace any of the components during maintenance.
For more FAQ, see Respro® Mask FAQ
Respro® Masks are reusable 
Respro® Bulletin Board 
Will washing it too frequently cause any damage? I wash them inside a laundry bag.
The mask can be washed and to ensure good hygiene measures we suggest on a weekly basis, you place the filter and valves in a pan of freshly boiled water (remove pan from heat source before putting filter in) and let it cool down. remove filter unit and allow to stand dry.
This will remove facial oils that may build up over a period of continuous use and ensure that it is hygienically clean. This procedure will also remove some of the particulates and organic vapour that will be present within the Charcoal structure of the filter or tissue salt build in the valves. If the mask cover (Shell) requires washing this should be done by carefully removing the filter assembly and then washing it in warm soapy water and then left to dry naturally.