Ok, my R12 sniffer arrived from Ebay...
the guy had not checked it out and the batteries had leaked.
He apologized for not even opening up the back and said he would refund..
but he asked if I might be able to clean it...
So I got the actual battery connections cleaned and installed new batteries.
The light lights up.... checking for beeping comes next.. I have nothing with R12 in it at this time...

HOWever, the question is this .... the leak went into the inside of the working mechanism electronics.... how bad I don't know....
But I would like to open that up and spray something which will either clean that crud out.... or neutralize it without hurting the electronics...

And I know some of you have this kind of knowledge to share with me...
Thanks, Greg

PS. It was only a $35 dollar (delivered) Texas Instruments sniffer... but I would like to have it work as long as possible and will not feel good about acid being inside it....

__________________
1980 240d ,

chain elongation, cam marks reference:
http://www.peachparts.com/shopforum/showthread.php?threadid=10414

http://www.peachparts.com/shopforum/diesel-discussion/305365-9-degrees-chain-stretch.html

evap fin cleaning:

http://www.peachparts.com/shopforum/diesel-discussion/156207-photo-step-step-post-showing-w123-evaporator-removal-1983-240d-1982-300td.html?highlight=evaporator

A/C thread

http://www.peachparts.com/shopforum/diesel-discussion/297462-c-recommendations-mb-vehicles.html