If you are spraying and the solution is dripping down the body you definetly have the dial turned up too high, if you turn it down so nothing comes out then gradually turn it up until just enough spray comes out (I then have marked the dial with a silver pen so I know roughly where it should be screwed up to).
With regards to cleaning the gun, you need to twist the dial completly at the back until it comes out, then squeeze the trigger fully and the needle will appear out the back, pull the needle out (this is REALLY hard first time, but just keep pulling straight), once thats out clean it under the tap, it may have stained brown a little but thats fine, leave to dry and then place back together-making sure you dont lose the spring out the back.
hth's
x