[Histonet] waterbath residue

[path lab]

Our waterbaths leave a good amount of black residue on our paper towels when
we dump the water and wipe them out at the end of the day.  Is anyone else
having this problem?  It appears that the finish is gradually wearing off.
 Could this be the cause of the   artifact ( black specs appear to be on top
of the tissue ) that we occassionally see?  Thank you in advance for your
replies.