When mailing a package, it's important to make sure the shipping label is legible, even if it gets soaked in the rain. Luckily, all you need is a candle to cover it with a weatherproof barrier.
Once you've printed your label or written out the shipping address on the box, wait for the ink to dry then rub it with the soft bottom edge of a candle. This will create a thin wax layer over the ink, causing water to bead and run off of the label instead of soaking into it. This won't protect your package from prolonged exposure to the elements, but it'll keep the ink from running during an unexpected sprinkle.
Check out the source link for more creative uses for candles.
Simple & Smart Housekeeping Tips: 5 Ways to Put Your Old Candles to Work [Apartment Therapy]