I learned something new: milk doubles as glue. Use it for jam; use it for beer! It's easy and cheap, and dries nearly clear! (Sorry; after I typed the first sentence I couldn't stop myself.)
A few days ago, a commenter asked about a good method for affixing DIY printed labels to jelly jars. Andy Biggs, mastermind behind the
Beer and
Jam Labelizers, mentioned he uses milk to glue labels to his bottles of homebrewed beer. What?!? After a bit of internet research, I learned this is a common method in the homebrew beer community. Labels need to stick on securely, but be removed easily so the bottles can be reused.
Must. Test. This.
A preliminary note: don't try this with inkjet-printed labels! The ink will bleed and run if it gets wet. Stick to (har har) laser-printed labels, either color or black and white.
Use whole milk or 2% to wet the back of the label. Then just stick it to clean glass.
(I've read that skim milk doesn't work well, but haven't tried it. It's probably similar to using just water: the label clings while wet but falls off when dry.)
When the milk has dried, the label is stuck on firmly. See? It tears when you try to pull it off. But when you run it under water and get the paper wet, it peels off easily with no residue left behind.
If you need glue that's even stronger, try a recipe using gelatin.
I read about similar concoctions in several online forums, then tested and modified a recipe.
Homemade glue ingredients:
2 tablespoons water
1 packet unflavored gelatin
3 tablespoons milk
Put the water in a small bowl and sprinkle the gelatin over it. Wait about 5 minutes. Then microwave the milk to nearly boiling and add it to the gelatin. Stir until the gelatin is completely dissolved. This recipe yields 1/4 cup of glue.
The glue will look like this. Brush it onto the backs of labels while it's still warm and liquid. When it cools to room temperature, it becomes a solid gel. You can heat it for 15 seconds or so to liquify it again. Or you can eat it if you're hungry.
As you might imagine, the milk will spoil eventually, so the glue mixture will only last a couple days.
The milk-gelatin glue bonds paper to glass even more strongly than milk alone. It requires longer soaking in water and a little more rubbing to get the label off, but again, it comes off cleanly. No need for solvents to remove any sticky, gummy residue.
These tricks would work well for sticking posters to windows or mirrors, too.