HP Probook 430 g4 keyboard maintenance

I have got a used laptop hp probook 430 g4 with the chiclet, not backlit keyboard from my cousin.
The problem is, he has a custom of eating in front of the device. As a result the keys' feedback is meshy, slow, way too smooth and lacks the proper tactile response. I assume it's due to the crumbs ad debris that accumulated beneath the keys.

How do you guys maintain this keyboard? Is it possible to uninstall the keys one by one and remove whatever is beneath them? Or, because it's advertised as waterproof, could I dip the keyboard in some kind of slovant for a day and than dry it?
I tried to do it with tiny piece of paper inserted between the keys and the board but it neither improved the feedback nor removed the debris under the keys. I have heard that some people try cleaning the area beneath the jeys with compressed air, but, honestly, looking at the gaps between the board and keys, I doubt the effectiveness of this method.
To make things worse I cannot find any retailer on the internet that sells keyboards for this laptop
EDIT:
I have found a retailer on ebay that sells compatible keyboard, a backlit one for around 30 USD.
He claims it's refurbished and original:
https://www.ebay.pl/itm/HP-Probook-...854819?hash=item3ad8876423:g:48QAAOSwmPdZuUVP
Shall I trust him or not? It's the first time I am considering buying laptop parts, yet alone via internet I don't know what to expect and I would really appreciate some feedback.

The reseller has 99.5% positive comments but so does a chinese retailer who sells either the same product or it's counterfeit for half the price so I don't know what to expectt