Place the chocolate in a plastic or silicone bowl and microwave for 30 seconds. Stir well with a spoon or rubber spatula. Microwave for another 30 seconds, then 15, then 10, then 10 seconds, stirring well in between each heating. The most important thing is that the chocolate does not go above 90ºF. Use a candy or probe thermometer to check the temperature of the middle of the melted chocolate. If it is ever too hot, keep stirring to incorporate air, and add a few pieces of un-melted chocolate to cool it down. If necessary, continue with 10 second intervals, stirring and checking the temperature, until smooth. Use the back of your spoon or spatula to spread some melted chocolate on a piece of parchment paper. If it starts to solidify in a few minutes, then your chocolate is good to use.