When I did the most recent brake fluid purges (300TE & 500E), I drilled a hole in the reservoirs and sucked out ALL the fluid using my shop vac. I then pulled the old reservoirs (without spilling a drop, as they were empty) and replaced them. When doing so, it provides you with the opportunity to clean the orifices leading to the master cylinder, which were a bit messy in the TE (which has always had its fluid changed every other year before my annual changes began). The reservoirs are cheap, and come with the two seals required.
Just thought I'd throw this out there, because keeping an eye on the brake fluid level is quite a bit easier with a new reservoir. Good luck!
"If everything seems under control, you're simply not going fast enough" --Mario Andretti
1995 E500 street car
1986 Porsche 944 Turbo S track car