Re: Welding spatter on my lense
The other thing you could try is Meguiar's plastic polishes. There is a cleaner, then finish polish, and a final finish polish.
This is used quite a bit by pilots. Many small planes have plastic polycarbonate windows. When I learned to fly, after finishing the pre-flight checks, I would polish the windows on the aircraft to get all or as many of the scratches off.
Since then I keep many of the Meguiar's plastic polish and cleaning products for the wind screens on my sport bikes, and I can polish my vintage Rolex watches with plastic acrylic crystals.
You can try this, however, if they are melted deep, the polishes may not work. You could buy a new window for less, as the products are not cheap. Although, the plastic polishes work on many, many things around the house, so you could keep them for other emergencies.
Hope this helps.
Good luck,
NR