One of the things I tend to keep is the plastic trays from packs of mushrooms - I used to buy my mushrooms loose and put them in the paper bags but I prefer the organic chestnut ones and they come prepacked - I use the trays to put under some of my housseplants rather than buying the plastic trays (the ones that are designed to catch water).

I was also going to use them for seed trays but when my parents moved Dad donated lots of the ones he couldn't take with him! 

I also keep the plastic containers that come with chinese take-out. I tend to make a lot of our food in bulk so I can freeze it - the plastic containers are just the right size for home made ready meals for two. 

I also use chinese takeaway boxes or ice-cream tubs for freezing leftovers - the children are often bitterly disappointed to find spaghetti bolognaise instead of mint choc chip when on a raid - amuses me tho'!!

Also find old plastic containers useful for watering outdoor container plants / grobags - cut the base off, puncture holes in or remove the top, insert upside down at base of plant then fill with water which then  leaches into the soil - small holes in the lid means slower flow - useful for  if you are away for a day or 2.  Glass jars also good for a) refilling with scrummy homemade jam, or b) filling with dodgy home-brew (don't ask) & burying in the veg beds as slug traps.

The shredded paperwork that is not allowed in the recycling bags goes as hamster bedding tho' can also be composted.  We have also composted worn out cotton clothes that are unfit for the charity shops - works pretty well.

read in a Sunday supplement today about a man who has invented various different types of screw lids that mean you can re-use a jam jar for all sorts of things eg a top with a pourer, holes for say sifting flour/sugar

What a truly brilliant idea. I really do hope the chap makes a fortune.

I keep my jam jars for our in-house jam maker - see above!

My old towels, newspapers, plastic trays and margarine tubs find their way down to the RSPCA shop in Long Lane. They use the trays as animal food/water bowls.

Good idea for these is to use them for planting beans & other long rooting plants - stand on a tray, fill with compost & plant in 1 or 2 beans per tube.  When big enough they can just be trnsplanted direct without disturbing the root ball as the cardboard will rot down in the soil.

Interested to hear about the jar top man - tho' in my experience lids & jars have so many varieties (even if they are the same size) that it may be hard going to find a jar it would fit properly.

Wow, what a great idea! I used to use the coia pots for seeds - though since my dad donated lots of plastc trays I haven't bothered - but now I will be saving my loo roll tubes and using those instead

Very good idea. I will use that one at work in the future. I really value ideas like that. Keeps the cost down too. I wish I could come up with ideas like that. Keep them comming