I buy these types of soup pots as they are easy to cook, just stick them in the microwave and voila a nice meal but that's not the end of them by a long shot. They have a resealable lid so can be used for many things.
Depending on what you want to do with them will depend on the tools you will need.
Step 1: Mini-greenhouses
They cut easily so if you want to use them in the garden then,
an 1/8th drill bit
craft knife (to remove burrs mainly)
Clean them out then take the drill and drill about 6-8 holes along the side near the base at its lowest point, this allows you to place it on a smooth surface but still allow water to flow out. Use the knife carefully to remove any burrs which might get stuck in the hole.
That is that, now add compost and plant a seed, water it and loosely put the lid on, this will act like a mini greenhouse, I press it on at the back then it doesn't fall off when you move them. One great thing about these pots are that they are almost the same size as a Bulb Planter so by making a hole with one you simply remove the plant and soil from the pot and place it into the hole without disturbing the new roots.
Step 2: Coffee/tea Filter
By taking a pot for the garden and another one and cutting holes in the bottom, I made a coffee filter for coffee grounds from my coffee machine. I placed the one shown above inside one of the mini greenhouse pots, putting a square of kitchen towel between them and pushing them together. Put some water in it to soak the towel then it was ready for use to put my leftover grounds in so they would dry ready for composting or just sprinkling on the garden, as it saves walking down the garden every time I had grounds to dispose of and it keeps my recycling bin free from the grounds messing it up. I clean out and put mine through the dishwasher once a month as if left too long mould will start to appear, the coffee soaked towel can be put in your compost too.
Step 3: Storage
I also use them for storage, after all a man can never have enough storage. If I am doing a project I store the components in them so I do not lose them or if I am repairing something I keep the fiddly bits I have removed in them.
I am thinking about using them as a water feeder for the birds too by drilling 1/16th or smaller holes around the bottom of the sides so the water cannot flow once I have the lid on. The pots have a really good lip for using hooks to add to a chain for hanging it.
I have no doubt you could find a use for them too, as now I never throw them out, I have so many uses for them.