Homemade Swiffer WetJet Cleaning Solution Refill Place your WetJet Refill upside down in a glass of pipping hot water for 5 minutes. This will help loosen the seal. Twist cap off. (The first time may be a little difficult.) Using a funnel fill container with 1 1/2 cups of Vinegar and 1 1/2 cups of hot water. Replace cap and insert into your Swiffer WetJet!