I wish, but not my egg cartons which are styrofoam and not accepted for recycling in my community. I would prefer to buy eggs packaged in the paper pulp cartons, but they are more expensive and harder to find these days. 
I also grind them in the garbage disposal.
Something else. They are crushed and mixed in with cracked corn that gets fed to the geese.
We don’t all live in the suburbs where humans have driven out all the big mammals. Composting food waste can attract raccoons and bears. I don’t know about you, but while I’ve made peace with raccoons I don’t like bears in my yard. That’s why we don’t compost anymore.
Disposal here. I definitely wouldn’t put them back in the carton, because I return the carton to the egg vendor at the farmers market.
Protip: have a garbage bowl on the counter. (God help me, but I picked up that tip from Rachel Ray’s cooking shows.) A mixing bowl or whatever, right there where you need it, to toss carrot tops, eggshells, etc. Then all the waste gets thrown out at the same time when you’re done - no dripping on the floor required.
I already do that when I’m chopping vegetables and preparing a meal, but a bowl just for some eggshells? Seems unnecessary when the carton performs the same task.
Really, back into the carton? Eww. OTOH you and your Ma both do it and no one is sick so…what ever floats your boat, right?
Eggshells go right into the disposal.
No thank you to composting. My neighbor does it with a tumbler and animals are always screwing with it. He keeps asking people to come shoot bears for him and I always think, “Yeah, I’ll get right on that, just as soon as you stop baiting them.”
Several days out of the month I walk on 'em.
I crack eggs on/over a piece of paper towel laid on the counter, put the empties there 'til I’ve got them all opened, then wad up the P-towel with the shells inside and carry it across the kitchen to the trash. No muss, no fuss, no bacterial growth 
I use ground-up puppies in my homemade chicken feed.
Regards,
Shodan
It’s the circle of life!
To the OP: What’s wrong with putting the shells back in the carton and then disposing of (or composting) them all at once before putting the carton back in the fridge?
In the spring, I crush them up and put them in the garden. The rest of the year, they go in the compost.
Nothing, I guess. I may do this just to keep the peace, although he’s not that bent out of shape about it. At least not as far as I can tell. It seems to be one of those minor disagreements that ends up as a peeve of the can-live-with-it-but-don’t-like-it variety. Honestly, I still don’t see what the harm is in letting them sit in the carton in the fridge. I never realized that I am apparently one of few people not grossed out by broken eggshells. Go figure.
Raw egg is the best growing medium for a wide variety of micro-organisms. The salmonellea, although it may have traveled in small numbers throught he micro-pores of the eggshell, has never before been bathed in the rich feast of egg that your fingers spread over their lair as you pull the egg apart and then stack one half inside the other.
Its also a convenient catch-all for whatever various bugs and spores may be flowing through your refridgerator’s air space. It catches them, and provides the perfect food and medium for growth. The only limitation at this point, (and it slows rather than stops growth in most cases) is the ambient temperature.
Each time you pull the carton out again, all those semi-dormant little grossites on the old eggshells get a few minutes at more conducive temps to take advantage of their good fortune. If your finger brushes one, they then get a new lease on life, and the opportunities are limitless.
TL: DR - Throw away the eggshells, Your Honey is right.
I put them back in the carton, as does my mom. I think it might be pretty common practice among people who have worked in restaurants or for large groups.
The eggshells dry out pretty quick, within a day or so I don’t think there’s anything that could live off of them anymore. I usually toss my shells into the trash but if I’m saving them for my plants I’ll keep them in the carton until the eggs are used up. By this time the shells are dry and I can crush them up without getting my hands all eggy.
I throw them in the garbage. My wife puts them back in the container.
We definitely don’t but them in the disposal - one time my wife made a bunch of deviled eggs for a party and shelled 18 boiled eggs into the sink. The disposal got clogged, but good. I practically had to take it apart to clean it out.
garbage disposal.
Other: garbage disposal