I have filed minor ridges from the basket before, although it's not a great idea. Because our hands are not accurate machines, we may file one "finger" more than another........causing uneven drive-plate contact. Uneven pressure can put bigger loads on SOME of the fingers (you don't want the basket to break while riding.) File it lightly, file it once......... if you file with the basket on the bike, ride it long enough only to warm up the oil and then change it. Save your pennies for a new basket and plates (worn tangs on plates will wear basket rapidly)