Modified crank

[RemCharger]

I have some cranks with all kinds of factory balancing , will post pics when I get a chance

 

[HawkRod]

I have never heard of using steel wool for balancing before.

The special steel wool is typically used where a crank counterweight has been drilled out to lighten it for one build, and then later for another build it needs to have weight put back into it. Mallory metal is very expensive and not needed for that type of repair. Even though this steel wool is specialized for this application (it is a mix of lead and steel), it is still way cheaper than Mallory metal.