I changed my brass float today, when I took the old one out it seemed clean enough but after I had put the new one back in, I noticed the old one had dried with a rust looking type oxide on it and it was powdery, is this normal for gas to do brass like that ? , or do you think I may have rust in my tank as I have the carb off being rebuilt and I am thinking if I have a bad tank it may have led to my carb problem.

Appreciate your guys input.

Claim to fame is the car was used as an extra in the movie Diner with Micky Rourke, Steve Gootenburg, Paul Riser and Kevin Bacon.