I used those types of containers to make rattles. Fill with pinto beans, tape lid on with duct tape, kid goes crazy shaking the container, you go crazy listening to it. Good times!

My son loves to put things in them (blocks, balls, his harmonica) and then take them out again. The lid seems to be easy enough for him to open and close. They might be fun as bath toys too!

Great ideas so far...especially the bowling pins! He won't be eating these too much longer, so you will stop collecting soon. He'd probably love stacking them and knocking them down. Since they have a snap-on lid and may fit in a drink holder, you could fill a couple with snacks for you to have on the go in the car. They would make great plastic grocery sack dispensers...one for the stroller, one for the car, etc. You could save a few for the various collections he will start in a year or so.

i ended up reusing happy baby puff containers for my own organizing needs... i have mounds of craft supplies, and lots of yarn specifically. so i removed labels, washed the containers and then used them to hold individual skeins of yarn that are now hiding in an ikea storage box.

you could take the labels off or cover them and use them as an advent calendar

Donating them to a an art center or to an art teacher is nice [being an art teacher:)]

I donated them to my oldest one's preschool and kept a few for colored pencils, markers and paintbrushes

They would be great for holding all sorts of different art supplies (feathers, pompoms etc)

get a bunch of inexpensive silky scarves, stuff them inside, and let baby pull them out. i did this with a wipes container. it was awesome. it's also fun to stuff pompoms in and dump them all out again.

Sorting is always a great activity for the little ones - these containers would work well for storing your sorting materials (think colorful pom poms of different colors and/or sizes, etc.)

i was going to say something similar to doubledutch. if you're a sewer or crafter, stick your spare scraps of fabric, ribbon, etc in them and let baby pull them out. it would be a fun busy activity while you get some cooking or dishes or whatever else done!

I refill them with other snacks... animal crackers, various cheerio flavors, goldfish crackers, etc and take them along. We usually end up leaving one at Grammy's house or in the car so there are favorite snacks wherever we go!

Use these for purchasing and storing bulk foods! For example, at our local Whole Foods, I have my containers (jars, bags, etc.) weighed at customer service on my way in, and the weight is noted on the container. Then, I fill each container with bulk foods--rice, granola, flour, salt, honey, you name it--and voila! Everything is already in its own storage container when I get home, so I can just label it and put it in the pantry.
I can't recommend this highly enough. You'll be able to reuse your containers, and avoid bringing new ones--bags, boxes, etc.--into your home!

I found that they work really well for packing soft, whole fruits in your bag. I'd fill it partially with cheerios for packing material and then would pop in a plum or a pear or a peach. I love taking fresh fruit, but I hate super bruised, mushy fruit.

I wish I had saved some of those! They're great to refill with other snacks (as others have mentioned) to keep in the car, stroller, etc.

I was planning on saving some for lego storage on the go. There are some other great ideas here, I like the rattles and craft supplies storage.

We saved a bunch, took the labels off and used them for my older daughter's Fancy Nancy birthday party. They glued tissues and "jewels" on them to make fancy flower vases.
If you don't want to use them, donate them to a preschool or art teacher for arts and crafts as bluepuppybites and Sendit2amy recommended.

great ideas! I'm taking our first flight with our 1 yo this month and I love the idea of stuffing the container with scrap fabric & scarfs -- what a great & quiet way to entertain a little one.

Wow - thanks so much for asking this question! What amazing ideas!

Now I feel so sheepish for recycling ours - but after insisting on keeping every single baby food jar, I didn't think my marriage would survive another hoard. ;) But these ideas are too good to pass up.

They'd make a good base for a papier mache toadstool 'top'.

Although at 15 months you can probably switch to an regular organic 'O' cereal and save yourself a LOT of money.