Yes i am searching for better endstops. But it is not so easy. I have contacted the distributor who sell them to Sintratec. It is a German Company and it is easer to get new one directly. The problem is that they found endstop which are water proof but not heat resit able or heat resizable but not water proof.
The problem is that the polymer are condensing like water in the air at cold glass. With the powder they stick at the contact. Right know i have changed 5 endstopper. (one at the door. two left, one right, bottom left) I have opened one defect endstopper.I have seen not really much powder, but there was e very thin resistor skin at the contact. After removing this skin mechanically and rebuild the endstop, it was working again.
Right now i want to print the following part for my Ultimaker:

www.thingiverse.com/thing:175621

In general i want to print some part from the inmoov project

SkullServoFixV1.stl