As with any item the uses are only limited by your imagination, so put your thinking cap on, while in the meantime here is a list to get you started.
Uses for the Plastic Containers
The plastic ones with the indents for your hand to grip the container are ideal for food scoops just as they are. No need to cut or shape anything. Just grab and scoop dog food, flour, sugar, or even water. A 50 pound bag of flour is hard to handle so why not break it down into containers such as plastic coffee cans for easier handling, and transportation.
Cut the can in half (save the cut off piece) and bore some holes in the bottom from inside the can for water drainage. Fill with potting soil and plant herbs for your windowsill, or use the containers for seed starters in the garden or sunroom.
3.) Use to Protect the Stem or Trunk of Small Trees or Plants
Use the cut off piece to protect the stem/trunk of certain plants by cutting the piece so it can open up around the stem of a plant to keep rabbits and other pests from gnawing the bark or stem. Squeeze the piece together to fit the trunk and secure with Zip Ties, duct tape, or twine.
In some cases, you may need to cut the bottom off a full sized plastic container and use it to protect the stem and/or truck of bigger fruit trees, for example. Once the container is around the plant stem or trunk you can fill loosely with mulch or newspaper to keep the roots warm or to retain moisture during hot summer months. Ensure you do not enclose the leaves of the plant within the container.
4.) Fill with Ice Melt For Easier Spreading
Scoop out enough for the job and carry the can with you to spread the ice melt instead of trying to dump or scoop from the bag. You can store ice melt in the cans and put in the garage out of reach of children and pets. Store sand or cat litter in the cans, as well, (used for traction), and keep one or two filled and in your vehicle.
5.) Store Used Cooking Oil with Newspaper
Once you have gotten all of the cooking use out of cooking oil what do you do with it. You can pour it off (after cooling) into a plastic coffee can that has shredded or wadded up newspaper in it. The paper will of course, absorb the oil. The soaked paper can be used as a fire starter. Just pull a piece out and ignite along with some dried tinder. You can also store the oil to use as a biofuel.
Uses for Metal Cans
1.) Rocket or a So-Called Hobo Stove
There is any number of ways to make a stove from a metal coffee can. However, certain rocket stoves may be hard to transport in bug-out bags, or survival kit. You can obtain gravel and sand used for insulation from your environment in some cases, so carrying, a metal coffee can and several smaller metal cans along with the tools needed may be worth the effort, so you can construct the stove along the trail.
The field expedient way to use one is to put some ventilation holes or slits in the sides near the bottom and build a small fire inside the can. Other designs would include the use of a fire chamber made from a small metal can placed inside the larger coffee can.
You would need to cut a hole in the side of both cans and insert a fuel feeder that reaches the inner chamber. You would also need an insulator such as sand or gravel to fill in around the fire chamber. This method is more complicated, and it may be difficult to transport, and it would require tools to cut and shape the metal.
A burning candle inside a metal container, such as a coffee can, can provide some heat in an emergency. This is particularly true in a confined space such as inside a vehicle.
2.) Bake Bread
Some cans may have a lip that would make baking bread more difficult. You can use the can as is or snip the rim in several places and push out of the way or simply use cans without the lip. Use your favorite bread recipe and prepare the dough as you always have. You will have to thoroughly grease the inside of the can. Use the wax paper cover from butter sticks, use Crisco, or even a cooking spray. Let the dough rise in the can, and once proofed bake the bread near a fire, or inside of an oven. If you bake using a campfire you will have to turn the can to ensure even baking.
3.) Survival Kit
You can store a number of items inside the can and keep in your vehicle or carry in a pack. Put the most used items on top so you do not have to remove items to get to the ones you use most frequently. Duck tape, cordage, fishing line, tackle, folding knives, matches and so on can be stored in the can. Have one in every vehicle.
4.) Wash Small Items
Wash socks, undergarments and bandanas, for example, in a metal coffee can. Add soap and water and the clothing and then cap and gently shake, or put in your vehicle while driving or pack while hiking. The agitation will work the soil and grime out, and then rinse well.
5.) Boil Water and Cook Food
Add a handle using wire or even cordage and hang over a fire to boil water for purification and to cook foods. A metal cooking container is invaluable in a survival situation, so always make sure you have one in your bug-out bag or survival kit.