Hand washing is always recommended. Use Cold water and a gentle liquid detergent free of optical brighteners. You can add a few tablespoons of white vinegar to neutralize the alkali traces and dissolve soap residue. Do not wring or twist. Lay flat on a towel and roll up to absorb moisture.
While hand washing is recommended, you can machine wash for a deeper clean. Use the delicate cycle with cold water. use a gentle liquid detergent free of optical brighteners. Be sure to use the shortest spin cycle.
Hang to dry(out of direct sunlight as it may cause discoloration). If you wish to use the dryer, use the heat-less, air fluff setting(cover the rings with a pair of socks so they don't bang around in your machine).
All irons vary so i suggest starting on a lower setting and working your way up.