I make my own strings and wax them well and burnish in with a piece of leather and never had an issue of grit on the loops but it can get some on it But I tend to it . I know wax keeps moisture out of the fibers and I take care not to rest my bottom limb tips on the ground and if I do I clean then re wax and "Inspect" the loops for any noticeable issues and if in doubt I toss it out and make another...Grit does act as sandpaper if someone sticks their limb tips in dirt,mud,snow,ice and so on but always keep it clean and try to take care and Inspect it often..I've seen loops that weren't waxed often and some fibers looked worn and faded in color and to me that's a string ready for failure and to me should of been waxed..To each his own but I wax and always will...