Plastic cleaning suggestions...

[interceptor44]

Don't know what these streaks/marks are but they are not coming off! Tried a few different things but with no success.....

 

[Igofar]

Judging by the location, direction, and appearance, I'd say someone spilled some brake fluid on your plastic while flushing or bleeding the clutch etc.
Don't think you will be able to do much with that.

 

[interceptor44]

Ok, probably one of the worst things to spill on your bike! Thanks.

 

[ST1100Y]

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Spray on, let soak for a while, use soft cotton cloth to wipe excess off and polish part up... repeat process where required...
Depending on environmental exposure it will wear off in 6~12 months, but IMHO the best stuff for those gray faring parts/areas on the ST1100 fairing, keeping the matte looks, won't grease up the surface... I even refurb the insides of instrument clusters, face-plates, plexi glass, etc... with it...
(this very product was also sold as Honda brand Spray Cleaner & Polish)

 

[bdalameda]

Try this - Stoners Trim Shine

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[SMSW]

I used Mother's Back to Black with limited success for streaks and stains from waxing adjacent painted surfaces. Try cleaning the plastic first with a mild soap, then proceed with the restorative chemicals.

 

[RaYzerman]

I would clean with soap/water, then wipe with a generous amount of isopropanol (it won't hurt anything but will dissolve residual oils/wax). Then see what you got. If you use a plastic cleaner like Back to Black, rub it in with a toothbrush and let sit a few minutes until it is almost dry...... then apply again over the first and while wet, wipe any excess off. Should improve it to some degree.
If not cured, wipe again with isopropanol, and if you're feeling brave, wet a cloth with acetone and wipe the whole surface. Feeling super brave, find a bit of MEK, it will dissolve/etch plastic and paint. You may be able to find a carb or brake cleaner that has it as a component.

 

[Ron]

Some brake cleaners will cause a worse case!