If you’re concerned about the environment, you’re probably already in the habit of refilling your hand soap dispensers instead of buying new ones. If you’re cheap, you’re probably already in the habit of refilling them with dishwashing liquid, because it costs less than hand soap. But if you want to be really cheap and conserve even more, you need to pay attention to the kind of dispenser you use.
Next time you’re low on hand soap, grab a bottle of the foaming kind. The pump on the bottle is designed to mix air into the soap, turning it into a foam that goes farther, spreads over your hands more readily and rinses off more easily than traditional liquid soap so you end up using less soap, less water and, ultimately, less packaging.
When the bottle is empty, fill it about 1/4 to 1/3 of the way up with dishwashing liquid (I’m fond of Seventh Gen’s lavender kind, but plain old Dawn or whatever will work as well), then fill it the rest of the way with water, leaving a couple of inches of headspace to allow room to put the pump back in. Screw the bottle shut, shake it up, and you’re good to go.
The fluffier you like your foam, the less soap you should use, so play around with the proportions to get it the way you want it.