A reason for gently wiping towards the knife edge, especially with a 
solvent dampened "Kleenex", is to keep the surface of the blade 
clean and polished so the cut section can slide easily over it, 
rather than "crinkle"
Attention should also be given to the Back of the blade and knife 
holder.
Be careful to let any solvent traped between blade and holder 
evaporate before cutting next section (and seeing it dissolve before 
your eyes!)

Russ Allison, 
Dental School
Cardiff
Wales