Looks like a rubber eraser.

 

How can i remove it?

 

Are you sure its actually "stained"? It kind of looks like the white finish is wearing away and showing the color of the resin underneath, which is kind of a brownish or grayish color. I have a gw-m850 that is showing similar discolorations on its white strap and case. If that's the case, probably not much you can do about it.

 

Looks like color transfer from bluejeans or clothing. Try a pencil eraser. This is why gloss white is better - it doesn't attract color dies.

BTW - the resin in my gloss white watch is white all the way through. I trimmed the strap end and it is not brow inside.

 

Probably not much you can do about it. I had a white DW-5600 that got stained while taking a wet rug out of the washing machine. I couldn't get it off 'cause the color soaked into the resin. A new bezel and strap will probably be the only way.

Greetings, Sedi

 

Have you tried a Mr. Clean Magic Eraser? I used one to get Sharpie marks of a table that had been there over a year. Never tried one on a G, but they do work wonders. Worth a shot...

Sent from the office of the reincarnated President of the Republic of Texas

 

My white GA-100 got cleared with pure rubbing alcohol on tissue paper

 

Wow, did no realiseCasio watch resins are susceptible to these color transfers.

 

Oh they're awful for it. I love me some colour on my squares but have to be really careful with any light coloured straps and bezels. I have an orange one that was really mucked up over a 3 day hike by rubbing against a jacket.

Jeans seem to be the worst for transferring colour. I have an all-white 5610 which I don't wear with jeans in order to try get a little more life out of it. Shouldn't need to baby a G-shock! [emoji31]

I tried a lot of different options to try clean up by orange set but I don't think I tried rubbing alcohol. I will give that a go.

Sent from my SM-G981B using Tapatalk

 

light colours will pick up and show dirt/colour transfer more than dark colours, even more so if the light coloured material is spongey rubbery resin, its no mystery or shock discovery. same way white shoes show dirt or colour transfer from other clothing.
you can 1. try cleaning it, which, depending on the "dirt" may or may not be an easy fix;
2. take extra care not to dirty it in the first place and minimise wears
3. buy replacement resin, wear without a care then replace as required.