When melting chocolate chips and thinning it out, people will often seize it. (Clumpy/grainy/yucky) If this happens; Start over and microwave in 10 second increments stirring well in between each time in the microwave. If you have a super powerful microwave you can change the power to 50%. When you add FAT to chocolate it helps thin it out without seizing it. Milk and water are a no go. Stick to Shortening or Butter