Many recipes require you to rehydrate dried mushrooms and reserve the liquid to impart flavor into your dish later. The preferred technique for rehydrating dried mushrooms in the our kitchen is to just cover them with water in a microwave-safe bowl covered in plastic wrap with several small slits cut into the covering. Microwave them on high for 30 seconds and let stand until the mushrooms soften, about 5 minutes.
When rehydrating dried mushrooms, lift the mushrooms from the soaking liquid with a fork so that the grit stays in the bowl.
The best way to remove the grit at the bottom of the bowl is to pour the soaking liquid through a small mesh strainer that has been lined with a single paper towel. The towel traps the dirt and absorbs a minimum of the precious liquid.