Watercolors should be framed with UV protection glass to prevent any damage from moisture or sunlight. Getting a watercolor wet will result in sever damage to the pigmentation and could potentially ruin the artwork.
Once a watercolor is framed, it will be easy to care for. Using a damp cloth (with glass cleaner), wipe away any dust visible on the glass and frame. It is not recommended to spray the cleaner directly on to the glass or frame as it could seep in to the artwork and cause irreversible damage.