Remember, when you go into the 'hanger' on the clipboard, there will be a pull down menu at the top of the list which should say 'default' on it. You have to scroll down to the skin you made.
Also remember that you have to make a text file in the directory of the new skin, and you have to name it (assuming you're using the p51d, for example) 'P51d'. Then you have to write the name you want the skin to have in the text file so it will show up on the aforementioned pull-down file.