Polka Food Storage Box Clips

I own quite a few Polka food storage boxes. They've been sold at very reasonable prices in their millions by Asda, Tesco etc. They have very good well-fitting lids. But whenever I took something like soup to work, I'd be afraid of the mess caused by leakages from the lid popping open. So I designed these clips to hold the lids on. They work brilliantly!

I've created an extra secure version which also achieved its purpose very well, but is much harder to remove.

And so you don't have to pri