Rubber on windscreen

[caroline]

I have a second car which is a Peugeot which my son drives.
The windscreen has marks left by the wipers, the marks are it appears of
rubber.
How best is it to clean this residue off, any tips welcomed.

 

[Mr. V]

Isopropyl alcohol and elbow grease.

Replace the wipers, and tell the driver to use his windshield washer
spray function more often.

 

[Peter Adler]

If it's rubber, try ammonia.

Pete (fP)