What do you do with old/damaged/imperfect MacBooks?

I've accumulated multiple macbooks of different vintages that I'd like to figure out what to do with. The issue is that they are usually not in great shape. I do have one from my wife that is in great shape, but I'm not sure how to "blank" that one before getting rid of it?

I also have a macbook pro from the prior model which has a bad screen. The keyboard is so-so, but the other parts are fine. Is this just something to give to an electronics recycling event?

Before I do anything, I'd like to make sure I'm not giving my data away.

So--what's your process?