Not Effective:
Bleach
Ammonia
Baking Soda
Alcohol
Effective Method:
Cat Litter (no scent)
Cat Litter Procedure:
Pour a layer of cat litter into a container large enough to fit the ice cube tray.
Place the ice cube tray on top of the layer of cat litter.
Cover the ice cube tray with more cat litter.
Cover the container and leave it alone for at least a week.
After a week, remove ice cube tray.
Wash thoroughly.
How to keep silicone trays free of freezer odor:
Only keep the silicone trays in the freeze when making ice.
All the rest of the time, keep the trays dry and in room temperature.