[Milsurplus] Enhancing or restoring the color of WW2 era varnished cotton insulation

[Meir WF2U]

Folks,

I'm working on my otherwise very good condition WW2 vintage TCM-2 US Navy
transmitter, except that a previous owner removed the original multi-pin
chassis connectors from the power supply and the transmitter and substituted
6 pin tube sockets. I managed to find chassis connectors identical to the
originals from BC-375 carcasses and I'm ready to install them. It's very
hard to identify the wire colors in the harnesses which go to the connectors
because the colors are faded to the point that for example you can't tell
between green and blue or brown and red, or yellow and white.  I managed to
trace the individual wires to the point that I'm 95% certain what they are,
but that's not safe enough for actually putting the transmitter on the air.
The wire colors vs. connector pin numbers are called out in the wiring
diagram in the manual, so being sure of the colors would make the
restoration easier and safer...
Are any methods, chemicals or trick anyone knows which can either clean or
restore the color of a little section of the varnished cotton insulation for
ease of identification? I can see this kind of color restoration can be
handy with other equipment under restoration.

Any input/experience is welcome.

Thanks,  

73, Meir WF2U
Landrum, SC