Tip for testing quality and performance of microfiber glass cloths, carry out this test at home when its dark go into a room where you have a mirror on a wall with a light behind you, proceed to wipe the mirror with a damp microfiber cleaning cloth, then proceed to polish off the mirror with your choosen microfiber glass cloth used dry, now you will be able to see clearly if there is any smears or lint left behind on the surface as the reflection of the light will show them up on the mirror, I have been using microfiber technology since 1994 and found this the best method to test for performance and quality, hope this tip can be of benefit and if there are any other tips for checking out performance i would be delighted to hear.