# Approximated complex numbers. How I put them to zero?

Dear all,
I'm fighting against complicated expressions which contain complex numbers that, after some calculations and simplifications, appear in a form like: 1. + 0.I. I think that this weighs down the next calculations.
The question is: how can I put zero the imaginary part? or, in general, how can I set a threshold for a number under which it must be considered as zero?
Thank you very much!

Teo

CompuChip
Chop[x]