How Long Should I Wait?
Well, how long is a piece of string? When the liquid came into contact with your MacBook keyboard, it immediately started finding its way under the keys. As the liquid spreads (depending on volume and how quick you were to act) it could have found its way into the very workings of the computer.
As you probably know:
water + electrical components = bad news
If your liquid happened to be some sort of sugary recreational drink or coffee, then the damage can be even worse, thanks to the high sugar content.
For an idea of how long to wait, find a tray in your kitchen, tip your drink over that, then shake it dry. Finally, turn it upside down. When the tray is dry, your MacBook should be dry!
If you’re in a rush, however, you might consider placing your MacBook in an airing cupboard, or close to a regular hear source like a boiler. Not too close, of course. We want the computer to dry out, not boil!