I have a Parker brush about a year old. I got it from amazon here : Amazon.com: Parker Safety Razor 100% Silvertip Badger Bristle Shaving Brush (Black Handle) & Free Shaving Brush Stand: Health & Personal Care. A lot of the bristles fell out for the first 6 months + that I owned it, but it has calmed down on shedding recently. However, I have noticed a greenish stain that is starting to form on the bristles near the handle. I'm guessing this is from Copper (I) in the metal (which is often green). Does anyone have any recommendations on removing this? Preferably without oxidizing reagents, as I do not want to bleach/weaken the bristles. Right now I am trying bicarbonate/salt, but will switch to something vinegar based.