My buddies and I reuse and recycle a lot of bottles and containers. The most difficult part is always removing those pesky labels! The easiest way I have found is to first pull off as much of the label as I can, and then rubbing baby oil into whatever is left. I let the baby oil soak in and start to break down the adhesive and then either scrape it off or just use a paper towel and rub off the rest. I used to be able to use hot water with the plastic containers, but many containers no longer stand up to heat.
Here's some of the things we have made:
Oil and Water Discovery Bottles
Milk Jug Jack O' Lantern