Clogged water drain line from fuel cap area

[Ernie Martin]

Is there an easy (read: inexpensive) way to clear a clog in a water drain line from the fuel cap area? I seem to remember blowing moderate-pressure air with a compressor from the drain end on the underside of the wing, but I'm concerned about causing damage. What about, once it's been dry for days, using a dropper to put some Drano down the tube? Any thoughts?

Ernie