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Is 303® Aerospace Protectant™ safe for Plastic Windows?

Answer: YES.
Actually, better than just "good", 303® Aerospace Protectant™ protects and dramatically extends the life of this clear vinyl windows. 

On the vinyl windows in your convertible top, SUV soft-top, or boat enclosures,  `303®' is the best thing you can do for plastic windows! 

What's the right way to maintain the plastic windows in my soft-top?

The material used for the `plastic' windows in convertible tops, soft-tops, boat enclosures, etc. is a specialized type of vinyl called `Pressed Polished Sheets', or 'pressed poly'. The material is actually two layers of non-colored vinyl laminated together under intense pressure and high heat. This process squeezes out all the impurities and renders it perfectly clear.

This material is soft and easily scratched and is not made in rolls but in sheets, which are separated by paper. Also known as `sheet goods', finished stock is always gently rolled and then stored and shipping standing vertically, never laid down. Pressed poly is known by its gauge - 20 gauge is made from two 10 gauge pieces, 40 gauge from two 20 gauge pieces, etc.

On clear vinyl plasticize loss and UV exposure cause embrittlement, yellowing and failure. Like all vinyl, clear vinyl contains plasticizers (to keep it soft and pliable) and UV stabilizers (to retard UV degradation)

Clear vinyl loses its plasticizers much more rapidly than top-coated vinyl. An UV protection added in the manufacturing process is less effective each day. Consequently, if clear vinyl windows on a vinyl soft-top are not properly cared for, they can fail within 2-3 years while the vinyl top itself will last for years longer. 

Cleaning: All manufacturers recommend first rinsing off the vinyl to remove any grit which might scratch the vinyl. Then using a little real soap (Ivory) in a bucket of cool water and a very soft cloth, suds up the clear vinyl then immediately rinse with cool water. (Never use cleaners or even detergents, just soap).


  1. Visibility: Minute scratches disappear for improved visibility.
  2. Resists scratching: 303® reduces the drag coefficient of treated vinyl to next to nothing. Deflects away abrasive touches that would otherwise dig in and scratch. Particularly important in applications where vinyl windows are continuously rolled up and unrolled.
  3. Repellency: 303® leaves a super-repellent, anti-static finish. 303'd vinyl repels smudges and fingerprints, takes much longer to soil and is much, much easier to clean when finally soiled. With 303'd vinyl all that is usually necessary is just to rinse it off before reapplying 303.
  4. Encapsulation of Plasticizers: 303® Aerospace Protectant™ bonds with clear vinyl in such a way that encapsulates and reduces outgassing (evaporative loss of plasticizers) to maintain softness and flexibility and significantly increase its useful life.
  5. UV Screening: 303® Aerospace Protectant™ is the only effective vehicle to achieve and maintain maximum UV protection. Periodic applications of 303® Aerospace Protectant™ will keep clear vinyl looking and performing like brand-new year after year and will dramatically extend its useful life.

Here's what a satisfied customer has to say about it:

"I was first introduced to 303 when I purchased a Downey SST  tonneau cover for my pickup truck.  Downey recommends your products.   It (303®) works great on my 1998 Sierra. 

But my story begins last October. 

"I bid on a 1965 Malibu SS convertible that was a drug dealer's car that had been confiscated.  It was totally restored 5 years ago.

"The county sheriff confiscated the car and used it for a drug program in the schools (The D.A.R.E program).  While the sheriff only put 300 mile on the car in 5 years, they let the detail work slide.

"As a result I have spent the last 3 months detailing the car.  I have used 303 on the interior vinyl for everything from the seats to the kick panels.  I used it on the five-year-old (vinyl) convertible top and needless to say, it looks brand new.

"However, tonight I learned the true value of your product.  I spent 5 hours trying to clean the convertible window.  5 years of neglect had started to show. I used a plastic cleaner followed by a liberal application of 303 and it looks brand new!  I removed about 1 ½ square yards of neglect.

"I think you have a wonderful product that has many uses." 
- Bob Wallace