ALAN81 said:
AS far as I know polyester doesnt take to dye and MF are 70-80% polyester .
Polyester will take up dispersed dye, but is typically dyed at 265F. It can be dyed at the boil, but requires some nasty chemicals to achieve this. (Unless you want to sire two-headed children with deformed extremities, or want large tumorous growths appearing - stay away from these chemicals)
Since most microfiber is Polyester/Nylon blend, perhaps you could simply dye the Nylon component (which can be dyed at the boil). Try WRIT dye (sold for household dyeing).
Writ contains direct dyes (for cellulosic fibers), acid dyes (for nylon and wool) and I believe also some basic dyes (for acrylic). These are all in a single mixture, and are made to dye whatever they come in contact with. The nylon will take up the acid dyes, and the other dyes will be washed away in the rinsing process.
Since the MF cloths are about 70-80% Polyester, dyeing only the nylon will result in a 'tinted' or 'washed out' appearance (as only 20-30% of the fabric is dyed), but it will acheive the purpose that you want (identifying different cloths for different purposes).
Writ dye is typically available in grocery stores, WalMart, KMart, etc.
