Jack at http://www.optotronics.com/ Sent me this and it works great on my RPL, my 30x Beam Expander and any front surface mirro i could fiend even my optic kit. and their both coated optics
" Here is my lens cleaning procedure.------------------------The best way to clean it is with one of those bulb w/ camel hair brushfor camera lens, they can be found at any camera shop.The less contact that is made with the lens, the better as even a veryminor scratch that the eye cannot even see can affect beam quality.Never use a cloth of any kind, (not even a "micro-fiber" cloth) unlessit is designed for lenses and it is new...i.e. you just opened/brokethe seal of the bag containing the cloth. The mistake most people dois that they get a cleaning cloth with some item, then it getsused,which picks up the dust and then reused which takes this dust itpicked up and scratches the lens.Never reuse a cloth for something that you don't want to get scratched.If the camera brush doesn't do it.Go to this site and get eclipse cleaner and some pec pads. Spray orput a drop of the eclipse on the lens and then use a "PEC" pad andlightly wipe the lens in one pass. If needed, you can do it again byputting on more eclipse and use a new PEC pad or a portion of the oneyou just used, just make sure it didn't touch anything else like yourfinger. After this, if needed you can use your breath to make a littlefog on the lens and use a new pad to wipe it one last time. IF thisdoesn't clean it then just give up as at this point you're going toend up making it worse by scratching it.After you open the pec pads bag and use them, put opened bag into aziplock bag to keep the dust out and be sure to never use the same pada second time.http://www.2filter.com/prices/products/eclipse.html
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Worked great for me