Eggs? How odd. Someone's either telling your mum porkies or has their wires crossed somewhere. As pica_nuttalli said, if they aren't cleaned out regularly then they might start to smell but that goes for all animals. Would it be possible for your mum to have a quick look at this message thread so that she can see how many people can vouch for their non-eggyness!
Millipedes can secrete an irritant if they feel threatened, which is why you should always wash your hands after handling them. But I've honestly never heard of, or encountered, millipedes that smell unpleasant and certainly not like eggs. It'd be a shame if you had to get rid of it for that reason.
Edit: Some species of millipedes are able to produce an unpleasant smelling substance through glands on the side of their bodies, but the Giant African Millipede (Archispirostreptus gigas) doesn't do this. So whilst cousins of the species you have are able to make a defensive smell the worst yours will do is secrete an irritant that can be easily washed off and doesn't smell. I've even been pooped on by these millipedes and it didn't smell of anything much, so I really don't think there's a problem regarding smell. Perhaps your mum read something about other wild species of millipedes and thought that yours is also able to make a defensive smell? Some people often claim that their millipedes smell of almonds! And how nice do almonds smell?!
/exoticpets.about.com/cs/centipedes/a/millipedes.htm
