How do I take off the keys of my laptop keyboard to clean them?

I heard this was doable.
But have no idea how.
Figured I'd ask around before taking a knife to them.

 

With my laptop I can just pull the keys from the bottom of the key (Under the letter) up and they'll pop off. Then I can just pop them back on whenever.

But I don't know if you can do that.​

 

My Dell's keys can just pop right off. I've discovered this a couple times while typing and my nail gets stuck beneath the key.

 

I've taken mine off before to clean away crumbs (lol). However, take heed- if you pull off the mechanism that holds them in place on accident, they are really damn hard to get back on. I lost my "e" for a while once ;-;