Back in the late 1970¡¯s I encountered the same tackiness in customer units. Is there any coloration difference or filming on the meter? Smoking in repair facilities was acceptable at that time and units we received from Greece and Turkey were particularly bad. We cleaned those units externally with a strong soap and water solution, then a 92% alcohol wash. All glass surfaces were then cleaned with the original Bonami glass cleaner (alcohol and a glass cleaner spray). If we needed to clean the inside of the instrument, we followed the previous procedure, after the alcohol wash we would blow dry the circuit boards with compressed air or oven dry the boards for an hour or longer.
The alcohol wash would significantly reduce the tackiness if it was due to smoking residue.
Don Bitters
