Using a new but potentially dirty olive and barb when shortening hydraulic brake hosing I wish to shorten the hose on a hydraulic brake system (model is TRP hylex) i have an unused TRP olive and barb, however unfortunately they have been knocking about in a tray with an old chain and general grime They aren’t visibly dirty but have been in contact with chain grime and i would like to know if they should be cleaned in a particular way before being installed. As it happens, without thinking i ran them under tap water so they are now also potentially contaminated with water. I’ve searched and can’t find any relevant info. Thanks

You can't 'contaminate' brass with water. Just give them a clean with isopropyl alcohol to get any dirt or oil off.