William Chops Westfield wrote:

> Don't use your good soldering iron to melt holes in plastic and such.
> Seems to result in either adding or removing a coating on the tip, and
> interferes with the solder's ability to properly "wick" onto the tip.
> (or such is my experience :-()

  PVC (plastic) is, for example, Poly-Vinyl Chloride.  Vinyl is
decomposable into Carbon Dioxide and water, but guess what the freed
Chlorine turns into and what it does to plating?

  Presumably, enough Platinum plating might provide a barrier if you
must use your iron for such things, but it is easier to follow the rule
never to touch plastic with it, and if you do at any time, to wipe the
iron on the sponge IMMEDIATELY and thoroughly.

   Cheers,
        Paul B.