ATTENTION: The purple tab must face directly to the left or the machine will not recognize this K-Cup Skills for brewing a Decent Coffee: ①Using Fine or Coarse grounds coffee. (Try a grind a little bit finer than table salt--definitely not espresso grind. (Sprinkle a bit of salt and grounds in your hand to compare.) ②Tamping the grounds coffee with good force Q & A： Q: Do you have to use the paper filters on these? A: It depends on you. The reusable k cup can do itself well, but the paper filter bring a finer one Q: It leaks from the top of k cup A: Use a Coarse/Fine ground coffee because if it's too finely ground it won't filtrate properly. Or be sure the lip closed tightly Q: Can't get a correct coffee, it's weak A: Do your own experiments to make sure how much coffee to put into it to get the brew strength/flavor you want. (Remember the ratios so that you can easily get a correct coffee next time.)