Guenther,
with a little patience and flexibility this is not a bad job.
only do this when the car is stone cold...
what I do is remove the linkage going up to thru the intake. clean and lube, reinstall last
then with a tool., typically a screw driver you can pop the long linkage off.
cleaning the ball is easy, if you want to clean the inside of the cup you will have to
get creative.
not sure if you want to remove the pivot itself, getting the lock ring off and on will be tough
but it can be done. remove the pivot, clean and lube and re install.
take your time , one tip is get an old towel or rag and lay it below the work area
if you drop anything it will fall into the towel and not drop to the floor maybe get lost.