You need to get Empty Vials first. The Seller of Strange Junk sells them if you can find him. Once you have some empty vials you can give them to Undercover Rebel at The Newbie Asteroid Belt [lvl 1-20] / The Islet Planetoid — Worshipping Point (10, 5). He'll fill up your empty vials with Plasma. You can then repeat as often as you need.
