(Quote From Website) Cleaning Process: Slowly push the mower blade into the brushes past the half-way point of the blade. Slowly pull the blade out, turn it around, and repeat. This will result in a clean mower blade, ready for balancing and sharpening. (Wear protective eye wear and gloves) Why is there 2 brushes? Wouldn't one do just as good of a job? Am I missing some thing?