Whitening a yellowish space bar on an IBM Model M keyboard: HOW?

[devhdb]

Hi,

I'm a newbie here so please don't bite me. 

I've used the Advanced Search on the forum and I'm sure that this question must have been asked before, but I've been unable to find it.

So, basically it's what the title says: I have used the suggested method to clean the Model M as per https://geekhack.org/index.php?topic=32995.msg623677#msg623677

Yet I have a 'rebel' space bar which, after the years has become quite yellowish and doesn't come out white enough as the rest of the keys. I wonder if it's made of a different kind of plastic...

What do you do to whiten/bleach key caps such as the space bar?

 

[hking0036]

All Model M Caps are PBT as far as I know, including the spacebar. ABS is usually what yellows. Regardless, you could take a shot at retrobrighting and see if that helps, but again it shouldn't really help since it's PBT, I'd just try giving it a nice scrub before going that far.

[devhdb]

Thanks por posting the link hking0036, I didn't know about that. 

I think I can give this a try. I'm happy to hear more suggestions in case other people have been successful with spacebars following other methods.