Is sneezing normal for a pet rat?

my rat i had to take to the vet because mukus came out of her mouth and nose

i sugest take your rat to the vet first, if the vet says there is nothing to do so the shower thing . Also, if you just got her, stress or the new environment may be making him/her sneeze. Allthough, your rat may also have an upper respetory(spell check, lol) infection, rats are prone to those.