I got mine working well again, without having to take the solenoid body off the other half... just cleaned it out through the valve holes, then propped it up on end and put a drop of oil where the shaft goes down into the bushing and let gravity cause the oil to seep down in for a few hours.
I did buy a replacement IAC, around ~15 years ago, so I take one off, clean and lube it, and swap in the other one that I already cleaned and lubed last time.