Emu XL-7 & MP-7 User's Group

I have the not uncommon encoder wheel problems (skips backwards and forwards when turned fast) and have read through some posts here but I'm still having trouble.

I tried cleaning it with deoxit (the little red bottle with brush) but even after seeing the photo someone had posted wasn't 100% sure hoe to apply it.  I coated the front contacts of the square part and sort of pushed the brush in into the two small openings at the bottom of the front.  However, I don't how successful this was at getting it in.  It's hard to tell if cleaning made any difference.  

When I got the unit it was in perfect condition but smelt like gumboots, and was probably tucked away in storage for a while.  I'm hoping it just needs cleaning.  

I read someone had poured cleaned into the actuall shaft and then lubricated it succesfully.  Is this  a dangerous idea?  How hard is to to solder in a new encoder given average soldering skills?