Some time ago after I'd bought more fresh produce than my refrigerator humid drawers could hold, I was in a quandary about what to do. I couldn't just cram it all in the drawers. It would crush the lettuce and I was sure to forget about something in there.
Reused lettuce boxes have a new home over the deli locker.Enter the lettuce box. I moved some refrigerator shelves around to fit them, and use them as spare humid drawers when I need them. Actually, I never put lettuce in the bottom drawers anymore; I just wash it, wrap it up in a goodish length of paper toweling, and pop it in a lettuce box with its tight fitting lid. Then the whole thing goes in the fridge. I once kept a lettuce that way for over a month. The ribs were a little pink, but I don't eat the ribs anyway- the rest of the lettuce was perfectly fine. I was pretty amazed that it kept that long, frankly. I used to keep the lettuce boxes on top of the humid drawers at the bottom of the refrigerator, but found that I can keep a better eye on them and be reminded of them better once I moved them higher in the fridge. Now the eggs and bacon can stay in the bottom of the fridge- they keep better down there in the coldest part of the fridge anyway.
I did once try to keep lettuce wrapped up in a clean kitchen towel in the lettuce box, but it soured to the point that I had to make a rag of it, which kind of defeated the purpose. Once the lettuce is all gone, I dry the used paper toweling over my clothes airing rack in the kitchen, and then use them to wipe up floor spills or suck up fat from a saute pan. So they get used a couple of times, too.
I imagine that for people with hobbies, lettuce boxes would come in handy for the small stuff that's hard to keep all together.
So hang on to them for those times when you've over bought at the Farmers Market because it all looked so darn good, or have something in the garden that has to come out that you're not quite ready to eat. They'll store it just fine.