The enthusiast community is very big into buy/sell/trade. Vintage shaving gear will almost always have been used before. Here are some things you can do to help protect against disease transmission:
Razors and hardware that is all metal or all hard plastic: Barbicide is the way to go. Use an old toothbrush and soap to remove any soap, whiskers, etc… and then treat per the Barbicde directions. I use a timer and let the item stay submerged for about 20 minutes. I then remove it as prolonged exposure can damage some finishes.
Brushes - Label instructions don’t include soft items like the knot of a brush. Personally, I take my chances and submerge the brush for about an hour. Note that this may yield a brush that is tinted blue. You can also let the brush sit for 2-3 months. While not an expert, Hepatitis C can live longest outside the body and can live for a couple of months or so.
Soap - A doctor I know that used to treat HIV uses the following practice. He lets the soap sit for two weeks, followed by skimming and discarding a thin coat off the top of the soap. He doesn’t consider this fool proof, though is comfortable enough to follow this practice for himself.