My husband (and his mother) put the empty egg shells back into the carton (in the same carton as the unsed eggs) and back into the fridge until all the shells are empty and then dispose the carton full of empty shells into the trash. Is this safe ? Can this contaminate my other foods or unsed eggs ? Gross!

I very much doubt it, that is a slightly weird practice though. Ask them to put the shells in the bin if it bothers you, I'm sure it's just a habit they've learnt.

My husband (and his mother) put the empty egg shells back into the carton (in the same carton as the unsed eggs) and back into the fridge untill all the shells are empty and then dispose the carton full of empty shells into the trash. Is this safe ? Can this contaminate my other foods or unsed eggs ? gross!
Thank you.

My husband (and his mother) put the empty egg shells back into the carton (in the same carton as the unsed eggs) and back into the fridge untill all the shells are empty and then dispose the carton full of empty shells into the trash. Is this safe ? Can this contaminate my other foods or unsed eggs ? gross! to multiply.

Gross, YES, This is probabably a tradition that should be ended. There are as many as 8,000 microscporic pores in egg shells. Bacteria and mild can easily find a path into cracked eggs. It may spread bacteria to other eggs, there are natural barriers that protect egg nutrients yet can provide nutrients for bacteria, these protector are (cuticle, shell, shell me,brane and albmen or egg whites). So those old cracked eggs that are still moist are waiting for bacteria to attack this wetness. Just not a good practice! :cool: