paint inside of oilpan?

["Paul Dorsey" <dorpaul@negia.net>]

Hi,
I've just had my oil pan dipped and cleaned with acid at the machine shop.
Although it looks shiny new, I wire brushed some areas.  Why did it rust some
on the inside where 30 years worth of oil and sludge had built up?
   Secondly, should I spray paint the inside of the oilpan?
Thanks,
Paul Dorsey- a long way to go
60 TR3a