Dawn or Ivory dish soap is always a safe bet. Even a sponge dries out, so you'll be fine. I'm sure it's a synthetic material so no shrink. Just don't use any kind of solvent or you might get the reverse.
Works great when you don't have a sink or hose available, especially in the winter. Spray on and rub/ wipe off with paper towels. I'm not sure what other trade names it's available under.
