How can I remove rain spots from vinyl windows

make a solution vinegar and water 50/50 add a dab of blue dawn dish soap and a dab of jet dry

Here's a video that might help you...I hope it does.....

Wash with vinegar water, rinse well, and dry with a microfiber cloth.

I use Oxiclean and warm water. It comes in a powder version in a small plastic canister that you can pick up at any big box store or in the laundry section of your supermarket. Read the directions. It will come out nicely. It’s a very versatile product. Good for laundry stains, vinyl siding, lawn/deck furniture without any bleach fumes. Good luck!