can't get my pin lock keg posts clean. please advise

[pricelessbrewing]

Tried oxyclean soak overnight. Scraping off with wooden utensils, successful. Don't think its rust. Probably moldy syrup/beer residue and/or mineral deposits.

Will attempt a soak in vinegar and starsan. The acid should work on mineral deposits.


Edit: http://imgur.com/IVK9Xvv Picture might help explain, anyone recognize what it might be and how to nuke it from space?

 

[GenIke]

barkeepers friend?

 

[pricelessbrewing]

Don't have any but I'll give it a shot.