Windscreen Watermark removal.

Watermark removal. Optimum vs Meguiars vs Osren

One of those free saturdays without appointment. So decided to conduct a mini experiment.

2 abrasive type polish (Optimum Hyper Polish and Meguiars M205) and 1 chemical based watermark remover (Osren Stain X - professional range) were used. Let the pictures talk.


Common for all cars. The rear windscreen is rich in watermarks. This one has plenty distributed out evenly.

Close up look.

Forgot to snap a picture of how was the windscreen taped up and divided. But below is a sketch.

Extra precaution was exercised by taping up all nearby rubber seals as Stain X is a chemical based watermark remover.

Results from Optimum Hyper Polish on polishing pad. Had to polish twice as the first time did almost nothing to the watermarks. As you can see, the watermarks are significantly reduced although not completely removed.

In case you forgot, this was how it looked like before.

A closer look of the reduced watermarks.

A photo on the border of the untreated and OHP treated side. (Left is untreated, right is treated)

For the Meguiars M205 treated side, these are the pictures. Polished twice as well. Almost same as the Hyper Polish. Not completely removed but significantly reduced (Left side is untreated, right side is treated).

In case you forget, it was like this before.

A close up shot of the untreated-left and treated-right side.

Now the Osren Stain X. This is the professional range Stain X (not to be confused with the consumer range stain X). Being a chemical based remover, one should expect this to be easier to use. Not so. High safety measures are required in using this. Rubber gloves and safety goggles is a must. Contact with skin, eyes, paintwork and rubber trims must be avoided at all cost. At least, that is how we like to do it. Protecting oneself and protecting clients' vehicles are paramount priority.

Stain X was poured onto a cloth and wiped on the glass. Pressure was applied and movement is reasonably fast. A damp wipedown and finally a good rinse completes the process. Pressure is required due to the terrible amount of the watermarks. Fast movements were used to avoid product drying. Thus the tricky part is working around the glass-paint border as there is a risk of rubbing onto the paint by accident.


No trace of any watermark.

Remember before.

A close post-treatment shot.

Take a look at the 50/50 shots

A close up 50/50 shot.

A total view. The whole rear windscreen was then finished flawlessly with Osren Stain X.

Easily, the winner is Osren Stain-X. By a mile! My preferred choice for watermark removal from now on. This is however not recommended for the front windscreen and aged side windows due to its strong concentrated nature.

For consumers and hobbyist, perhaps the regular Stain X will do. It is a toned down version of the professional range. I would expect same amazing results with a little longer working time. But rest assured that it will not inflict severe damage your skin or paintwork should you accidentally spill it.


Just one of the regular experiments we conduct to find out the best available treatment for cars that we do.
Thanks for viewing.