Hello MS Brim;
Your lens is not coated and would remove the elements to clean. I use microfiber cleaning cloths and a good glass cleaner. Blow the crud off first and flood the element with cleaner to float any abrasive off the glass. Use your fingernail with cloth to get into tight corners and scrape off spots. A push on filter holder with an old skylight or light yellow filter might make a great addition, Steven.