The best replacement for stopper is sweeper.

The best alternatives to stopper are rated as following:
★★★★★  sweeper
★★★  bump patrol
★★  bung
★★  hitech
★★  tend skin
★★  cork
★★  runasdate
★  dividend pusher
★  nd110
★  liquid fence
★  nd400
  hoya nd400
  sweeper in soccer
  sweeper soccer
  stopper
  carb stopper

Your alternative for stopper is not listed? Suggest!
Speaking about stopper, one probably shouldn't forget about glass tube.

Other search terms related to stopper and their ratings are:
★★★★★ glass tube
★★★★ airlock
★★★ vacuum pump
metal pourer
You have in mind a companion for stopper and it is not yet here? Propose!



Google Trends

Scale is based on the average worldwide traffic of stopper in all years. Click on graph for more.
stopper
sweeper
bump patrol