you could but if any drips down the side, you could ruin the keyboard. maybe use an external keyboard.
I have a Samsung NP700Z3C-S02UK and I love the spec and performance but I am on my 2nd replacement laptop and 3rd keyboard as the same letters keep wearing off of the keys and I am desperate to find a solution to this. Can I paint clear nailvarnish over the top of the keys? Samsung have not been able to provide me with any help.