How to know when MF is no longer good?

[AutoNova]

Trying to weed through all my Mf towels and pull out the bad ones, how do you know when they are no longer good? i tried running a CD over them but that did not help?



Also does anyone know a way to mark towels that will not wash out, I have all yellow towels but want to mark some for just windows?

[Wasatch]

To keep my MFs separate, I keep them in different bags and boxes.

[imported_Dave Holmes]

To mark them you could use a permanent black marker.



I haven`t worn any of my good ones out yet, meaning they still work/feel as good as new (exceldetail`s towels I got last February or so). My "grunge" ones from Walmart have gotten stiffer with age, so I guess that would be an indicator (they are clean, just not nearly as soft).



Dave