Safe way to use Dark Zone keys?

I've accumulated 17 dark zone keys, but I never go into the dark zone. I'm near the carry limit of 20, does anyone have suggestions for how I can safely use them, and where on the map to go to use them?

I'm a solo PvE player, SHD 600, but don't have a PvP optimized build. Two main builds are HF/Scorpio/Memento and a Catharsis/Deflector/Liberty build. I'll probably take the scorpio.