If debris in your oil clogged your solenoids your bearings must be in excellent condition.Oil and oil sourced debris. The solenoids allow oil to flow into the VANOS cylinder, effecting the placement of the intake cam. So... Oil moves over the solenoids, which eventually accrue small amounts of debris, impacting the ability of the solenoids to fully fire.
Of the eight, only one was fully firing when he started cleaning everything. Three just made noise, but didn't actually move. After cleaning them, all 8 are fully firing and should allow for the VANOS to do its job, which is adjusting the cam positioning.
I put in new cam position sensors last week too, so together, they should bring a substantial amount of power back to the table.
http://www.eeuroparts.com/blog/articles/557/bmw-vanos-explained/