During the process of final inspection, and just before packaging, we check our phone bags for loose, stray threads, or lint, etc. Our quick and thorough method for cleaning bags is to wrap packing tape around two or three fingers. We have yet to find a quicker and more thorough method for doing this. Plus, it's not a single use purpose, packing tape is always available and part of our routine supplies. We use it every day for shipping products to customers and cartons of products to Amazon.
We include one "Cleaning Tips" card with every cell phone bag we ship.