Vintage Synth Repair

Greetings,

My Taurus II pedals power became too intermittant.  The connector seemed 
to be the problem so I openener up the synth part to find that one 
connection on the power jack HAD NO SOLDER!!!  So I soldered it.  
Unfortunately, now there's another problem.  The black insulator pad 
between the PCB and faceplate has deteriorated into an inky mess that 
disintegrates as you touch it and has left its residue all over the 
place, mostly oin the electronics.

1.  How do I clean the inky mess off of the electronics?
2.  What should I use to replace it?  Are there any diagrams showing the 
insulator's proprer placement?

Thanks!

Bill Fox