Thanks to all for compliments...
The wear basically I made with powder of pastel chalk (black, earth and sand), some bits of rust paint (by Testors) and the chipped paint I made with a fine brush (000) ...
I use a moderate wash with Betume of Judeia for dirty in the wheels and low-relief and the tracks I followed the article "Weathering tank tracks" by Lynn Kessler - FSM September/2002 - page 60.
When I have more pictures, I post for you.....is a pleasure sharing it with you...
Thanks again