How do you keep a camera lens clean? You cover it with a filter. But how do you keep the filter clean?
I floundered for many years with streaky Kodak solutions and other goofy products, till I was referred to a mysterious product called Pancro by an extraordinary AC named David “AC Dave” Wendlinger. Pancro comes in industrial white bottles with a big sticker on the front, “PANCRO Professional Lens Cleaner Non-Streaking Non-Residue Non-Toxic Fast-Drying” (almost poetic).
Who knows what it is. But it works like magic. Now my lenses are spotless. This stuff cleans anything with glass; binoculars, telescopes, cameras, rearview mirrors. I carry a little bottle of it in my pocket for my eyeglasses. A pack of Rosco Lens Tissue goes well with it.
Best practice for cleaning the lens/filter? First, hold the camera upside down with the front lens pointing down. Use a little blower with SOFT bristle brush to blow off any particles from the lens surface, particles which will fall off the lens aided by gravity. Put a few drops of Pancro on the Rosco lens tissue and softly polish the lens in a circular motion. Rotate use of the 4 corners and both sides of the tissue so that you always are using a clean part of the tissue to avoid grinding grime into the lens surface. Repeat upside down brush operation if necessary. Inspect with extremely bright flashlight pointed at angle to the element. Some people recommend a cloth instead of the Rosco paper, but I’ve found them too fussy to keep clean and free of abrasive particles. Canned air can work as well, but it can streak the lens if Freon is accidentally sprayed when help upside down or sideways. And it can’t be checked in baggage legally.