How do I clean an IAC motor on a 1994 E-150?

You can remove it, run the screw out all the way; then use Brake Fluid Cleaner to attempt to clean the plunger - do NOT spray it into the motor control only use an Electronic Cleaner for that section. Be sure and run the screw back in before you put it back on (it will idle bad for a while until the computer resets it) - and this will only work to 'fix' the problem caused by the IAC in about 1 out of 100 cases.

Do not attempt to sand, polish, or use any form of abrasive on the unit.