If its mold beach will kill it and change its color immediaty to
within 5 minutes.
If its effloresence Acid such as muriatic will remove it visualy
affect it immediatly to within 5 minutes..
Effloresence feels like chalk or grit, mold can be fuzzy or have 100
different visual charistics depending on type., White, black, green,
If its neither just wash it away with soap, its probably from the