You can clean it if you can get it apart... for a lot of folks, the first one is going to cause some damage as you learn...
But the biggest problem is convincing your spouse you should be allowed to do it.

You remove the keyboard, and other parts... remove the ribbon cable from between the bottom and the screen side,
Then it is a matter of removing the screw covers then the screws... Depending on the laptop model, there can be as few as 9 or as many as 33 screws holding the screen side together... and more to get to the back of the screen in some cases.
Easy enough to clean with a mixture of distilled water and denatured alcohol.
Even putting it back together is not that difficult, until the last part which is the replacement of screw covers. If you have never done it before, and if you do not have a new set of screw covers, the results can be a great deal more ugly than the watermarks in the back.

Shop/search for the replacement screw covers first... once you have those actually in hand, take on the rest. You will need high quality steel long, medium, and short #0 philips screw drivers. Some of the screws are held in with the blue screw sealing compound, so you may need some of that at the end.

First laptop will likely take four hours, if you are good with tools and your hands.
After that, you can do them in 20 to 30 minutes, start to finish.
Newer laptops may have new style connectors and screw covers... I haven't looked at an acer in nearly a year.

 

Very good, Thanks Raybay.

 

I believe what you're referring to here is what we used to call "Q dope". This is more of a tamper preventing luxury than a necessity. The manufacturers use this as a safeguard to enable them to void the warranty, if it is obvious that a broken machine has been opened by someone other than a factory authorized service center.

So, there really isn't a structural need for this in most cases. Although, if your laptop vibrates like the dickens, better put it on to make sure.

 

It will leave some watermark traces,suggest buy a new LCD
If you clean the Lcd you might damage the board of the LCD,just make sure not to touch the board.

 

Properly done, we have never seen it leave water marks... but that is only on 11 machines... not many get water in them.
Properly done, you will not harm the board at all... But if you are not good with tools and screws, assign the job to somebody else.