I just completed a complete resto on a GE-805 Locomotive. It looks and runs great now. I did a cosmetic resto, and it looks like it came out of the box.
To "reflock" the top screen I ran down to the Hobby store and bought some Railroad Modeling artificial "dirt", which had a similar color and consistency as the origional flock.
After cleaning the screen with a vaccuum, I sprayed it with spraymount, and added the "dirt". Presto. Instant Flocking.
But, if this stuff is available in a spraycan, go for it, as it's probably much easier.
Best of Luck;
LJB