major overhaul of a cd-player

[jupiler]

Hi,

I'm very new to this forum, but from what I've read so far is excellent stuff!
Now my post:
I have 2 DENON dn650f cd players, around 5-6 years old, pro stuff.
They served well, but never really got maintenance. So here's what I plan to do, and I would welcome your ideas/comments:

Replace the laser-units (KSS240A).
THey've been cleaned before, but both now occasionally can't read TOC, skip, etc.
Q's - does it make sense to remove the lens and clean both sides?
if the complete unit is replaced, what adjustments must be made?

Clean and re-grease all moving parts
This means the cd-tray, the platter, the motor spindles, the laser drive slead.
Q's - what solvents to use to effectively remove old oil traces from the motors? Could I rince them in a bath of solvents, dry them and re-grease?

Replace drive belts
Maybe not immediately required, but since I'm taking the unit apart anyway.... and these are cheap :-)

The ribbon cables from the laser unit to the mainboard measure ok, but would you advise me to replace them also?

thanks all of you for your good support!