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IBM model M has 5 keys that do not work. How can I clean those contacts in the membranes? Answered

The keyboard is in excellent shape otherwise.  Can I puncture the bottom metal shell in the locations in trouble and then inject contact cleaner?  Are there some other vent holes that might be used?  Could it be an electonic problem or circuit board plating in those areas?  The five keys affected are :
g,  h,    apostophe ,   up arow,  and the number pad zero.


Was something spilled on it?
Injecting cleaner is not likely to work, it'll need to be disassembled and inspected before anything else.


The model M isn't a membrane keyboard. See https://www.instructables.com/id/Clean_your_vintage_IBM_M2_clicky_keyboard/ for one approach to disassembling and reassembling it.

Note that quite often, the problem is just something caught under the key, or a key that wasn't reassembled properly.  You usually don't have to disassemble unless it has been pretty seriously abused.