Did you know that you can disinfect your masks and mouth pieces with Hydrogen Peroxide? It will kill funguses, viruses and similar while it does not affect the silicon. Make a solution of 50% distilled drinking water with 50% peroxide and let the masks and mouth pieces soak in there for about 10 minutes, rinse it with water afterwards.
When operations resume you could choose to buy stock of mouth pieces and resell those to your divers. When every individual has their own personal mouth piece it will give a sense of extra safety! Aside of the safe feeling for the divers, it saves you a little bit of money too.