This article is from the Chrysler-Plymouth-Dodge FAQ, by Dr. David Zatz with numerous contributions by others.
David J. Allen quoted (e-mail address removed).mil as saying that, when his
89 Caravan sometimes made a loud CLICK instead of starting, he saw that the
starter solenoid contacts were eroded down the thickness of a penny.
Vandamme soldered a real copper penny, filed to the shape of the missing
electrode, into the space.
David J. Allen wrote: [On my 88 Caravan,] I tore the starter down and found
that the contacts had worn down to the point of only providing intermittant
contact when engaged. A friend of mine brought me a couple of strips of
1/8" copper from work which I cut and formed into new contacts. They fit
right in and I haven't had a problem yet (1 1/2 years).