Be careful about soaking (submerging) anything electrical in solvents.The solenoid or stepper motor windings,etc. can be damaged.

three solenoids on mine. Of course applicable cleaning procedures should be used on any electrical components.

So nothing builds up on the inside of it? I've never taken one apart, so I don't know what it looks like on the inside.

My old 1990 Lesabre had the three solenoid digital egr valve.Had it off for cleaning a few times because of persistent check engine light.Code 63 I believe.I just cleaned the carbon off the outside and made sure the valve pintles would open when pushed.Worked great until it failed. Was getting a quad driver fault code.Not wanting an old junkyard part I bought a new one at Pep Boys for for 200 bux (ouch!) because the mechanic there gave me the resistance values for the solenoid coils.One coil was bad.The new one (Borg Warner) was identical to the original.Even said "Rochester" on the coils.And I think it was lifetime warranty.Autozone wanted 160 bux at the time for a Wells brand with a one year warranty.