A microwave is finely tuned to stimulate the hydrogen-oxygen bond present in water molecules. Microwaves can actually cleave the oxygen-oxygen bond in hydrogen peroxide (a relatively unstable bond), turning it into water.
Without actually knowing the resonant frequencies of the specific compound bonds, I would say there is a chance for the molecular structure of your gear to rearrange if exposed to a tuned energy source.
Any weak or unstable bonds exposed to an energy source are prone to undergoing unwanted changes. All steroids have a four ring base structure which could possibly be susceptible to this type of attack. Any double bonds or weak hydroxyl bonding would be as well.
Jn summary, just heat it up in a warm water bath.