best brake line plug method?

I spent what seemed like hours bleeding brake lines after a newbie strut job on my '89 5spd D/R (left the front brake lines disconected for the better part of the morning). After a never-ending stream of air bubbles from all the bleed screws, I finally decided to put the wheels on and drive it (carefully, squishy pedal nearly to the floor) and then re-bleed.

Stuff a rag in the center of the fitting? Maybe someone makes a plug?

BTW, whoever posted the method of sealing the threads on the bleed screw with dielectric or vacuum grease, my hat's off. Makes the Harbor Freight vacuum bleeder tool mostly easy to use to pull the air out of the lines.