I did this too!
Worse yet, it was when my dryer was still very new (less than four months).
The only thing that worked for me was 91% rubbing alcohol and a lot of paper towels. Around here, 91% rubbing alcohol is at the drug store, not a general merchandise store. After that, I wiped the drum with a cloth dampened with water.
I've washed pens since then, but I have not yet dried another!
Good luck!!
Lawrence/Maytagbear