Crafty Failure

These are the super cute mugs I spent 2 hours creating this evening.  These are the super-cute mugs that I crafted using sharpies, just the same as I did last weekend on the little bowl.  Well apparently, the super cute mugs will never be used because my sharpie technique is not as fool-proof as originally thought.  After taking them from the oven where they baked at 350 for 30 minutes, I was able to wipe the stars right off with my finger.  But you say, the little bowl worked perfectly last weekend.  Yes I thought so too, until I grabbed it today and tried to rub a bit off, and surprise, surprise, the stars just disappear!  Dude, Seriously?! I'm quite perturbed to say the least. 

Any one need any Sharpies?  I've just bought handfuls thinking they were a sound investment for my new hobby...