Hi there, a very wise man I know who has kept them for years says that they will get used to your presence once they have properly settled into their new environment. It would be best not to hold them too often at all, but if you really feel the urge to handle them, you do need to make sure that you wash your hands first thoroughly with cold water and leave them wet whilst you handle the salamander. They will absorb toxins from your skin and as above, their protective mucus layer can be removed too. This is the case with the usual Fire's or Tiger's anyway, for the species that breathe through their skin (lungless sali's) I'm guessing extra care would need to be taken but I've got no experience at all with those types. I hope this helps!