The starter solenoid is part of the starter motor.
Hopefully you can click on this link and it will show you how to clean them. Not sure if unsubscribed members have access to this info though
http://www.the75andztclub.co.uk/foru...ad.php?t=25196
The how to is from a KV6 petrol but hopefully the 1.8 is the same???? not sure where the starter is situated on the 1.8 though
worst case scenario is replacement starter