It would probably be a good thing to drain it. The brake fluid will get everywhere and take any paint off it comes in contact with. If not you can cap the master with plastic plugs like they come with new.
While it is empty you can also clean any dirt that has gotten into the fluid.
89 2.5 TBI, 4" RC lift, 1" Booms, SYE, Adams Driveshafts front and rear, Ford 8.8 with 4:88s, BFG 33X12.50X15, and a ton of other stuff.
AF Jeep Club Tail Number 184