Loudly demand metric units from any American who uses any imperial unit
This pledge closed about 3 years ago
How this will help
Steadfastly refusing to engage in foreigner-speak has made the English language the modern lingua franca. The remnants of the imperial measurement system can be stomped out in the same manner.
When you hear anyone mention a fluid ounce or other obsolete unit, loudly state "what's that then?", and demand conversion to metres, kilogrammes, hectopascals, or some similarly sane unit.