Since there was still some brake fluid in the res, and the brakes were not applied, you could probably siphon off everything in the resevoir. Then remove the resevoir from the master cylinder and thouroughly clean it, be sure to replace the rubber grommets upon reassembly. While you have the resevoir off, you could also open the bleeder screws at each wheel and let the system gravity drain into appropriate recepticles.
Once back together, bleed the system and you should be good to go.
'73 280SEL 4.5 (9/72)- RIP
Only 8,173 units built from 5/71 thru 11/72
'02 CLK320 Cabriolet - wifey's mid-life crisis
2012 VW Jetta Sportwagon TDI...at least its a diesel
Non illegitemae carborundum.