When it turns clear, it's done.
Step Four: Meaning
The last step is adding a candle. The easiest way to do this is to choose a bead or other object that can comfortably fit a birthday candle inside. Attach the bead to the box and the candle to the bead. Now you have an object that looks as sacred as it actually is. (Don't forget to remind your giftee not to light the candle, as that will make your whole altar will go up in flames. Unless, of course, they're into that.)
See? Simple. Cool. Fast. Now rinse and repeat. The more you do it, the easier it'll get and the more elaborate. Experiment with bigger boxes or containers of different shapes. Get creative with puffy paint or stencils. Use fun fur or punk rock patches to turn your friend's whole automobile into an altar. (OK, maybe you should ask before you do that one.) No matter what you come up with, it'll sure beat a gift certificate for Best Buy.