[pianotech] cleaning key tops

[David Boyce]

Good point Terry, I agree. I was pushed for time, and simply said "nail 
polish remover might be worth trying".
I had in mind that a tech would proceed knowledgably and cautiously. I 
didn't intend any general recommendation to the OWNER.

Wim, I think you have rather over-generalised.  Nail polish remover may, 
or may not, CONTAIN acetone. It is not PURE acetone.  Caution must 
always be advised, proceeding by trying on a small area, perhaps the 
bottom of a key front. 

There is surely a very large difference between immersing plastic 
keytops in ACETONE for 24 hours to dissolve them, and a brief wiping of 
a plastic surface with nail polish remover. Cautious experiement is 
always advised of course, and it's what in my hurry I hoped would be 
inferred from "might be worth TRYING".

I have successfully removed sticky  residue from plastic key tops with 
nail polish remover, without adversely affecting the surface of the 
key.  And previoudly on this list I described the method I discovered 
from a customer, of whitening old celuloid key tops by skinning off a 
tiny layer of molecules of discoloured plastic with nail polish remover. 
I sent photos to the list.

If  we think about the marker pen marks on the keytops:  The best hope 
is that the marker substance will  sit on the surface of the key without 
interacting chemically with the keytop material. That is a best-case 
scenario, and doubtless a forlorn hope. It would certainly be easiest to 
remove, by scraping without damaging the key, or by a solvent ditto.
The next level of problem would be, that the marker pen chemicals had 
penetrated microscopically into the surdface of the plastic, but again 
without checmically  reacting with the plastic. In that instance, if one 
had the right solvent, the hope would be to use it to persuade the 
marker pen substances to come back out of the plastic, in a kind of 
dissolving-and-mopping process possibly innvolving capillary action.
The third level of problem, perhaps the most likely, is where the marker 
pen chemicals react  with the plastic and irrevocably bind to it 
chemically.  In that scenario, the only hope is to  remove the layers of 
molecules of plastic as deep as the pen has affected. This could be done 
1) mechanically, by scraping/abrasion or 2) chemically by solvent used 
judiciously so as not to damage the plascti cosmetically, to an 
unaccepptable extent.

This is all a long way of saying: nail polish remover might be worth 
trying, judiciously and with suitable caution.

Best regards,

David Boyce



> Test an inconspicuous spot first. Be careful with any organic solvent 
> - it may dissolve the key!
>
> Terry Farrell