Water trick 🤷🏻‍♀️

Has anyone tried the water trick on tests when your not sure if the line is a bfp or Evap and you put a drop of water on the test window to see if it goes away or not? Just wondering because I have a vvfl ( in the time frame it says 2-10 mins I seen it at like 3-5 mins) but still wasn’t sure if it was an Evap so I googled and it said do the water trick if it says it’s bfp and if it goes away it’s an Evap