Ilford anti-static cloth
I cut mine in half as soon as I open the package, and then store the other half in an air-tight container. When the first half is soiled, or no longer effective, it goes to be washed, and ends its life in my rag bin. If it hits the floor, or otherwise gets dirty, it is finished, as far as I am concerned, and goes straight to the rag bin.
To clean lenses, I follow the suggestion given to me by my Studio and Lab instructor, when I was a first-year student at Ryerson Polytecnic University, lo those 35 years ago. He said that the best way to clean a lens was to use a piece of an old t-shirt, or an old handkerchief, which has been washed many times, and so has had all of the lint and dust removed from it. It also gets a periodic washing, and with the clothes, NOT with the rags!
True story: when I worked for a large photofinisher 24 years ago, one of the employees' wives used to be supplied with the Ilford anti-static cloths, and she used to cut and sew them into small tubes, sealed at one end. They were used as negative cleaning devices, on the printer operator's thumb and index finger, with standard finger cots on the other digits.