I tried Autoglym Bumpercare on mine a few months ago, the results were dramatic, the 30-year old windscreen on mine had yellowed slightly and gone dull with slight crazing, it now looks like new. 
Tonic for ageing windscreens
- Thread starter John Roberts
- Start date
ELIMINATOR
Registered user
Oooh, removed the slight crazing.
Yup, I now have a far calmer windscreen, more at peace with the world.Oooh, removed the slight crazing.
ELIMINATOR
Registered user
Karma windscreen? 
Yes tried it out & you are right, much improved
