No a real castic hot tank will make them look like new, even eat the rust off. I used to use one quite a bit.
Most imoportant thing to remember on sb is to grind off the rivets holding the cover on the bottem of a stock intake to get it clean and clean the plate separately in the hot tank.
That is true when I took in the 340 intake they took off the bottom pan hot tanked it and reinstalled it. The unit came out looking just like the big block piece. In Washington they must still be able to use the real deal solution not sure what it is but it works sweet. I have a whole slou of valve covers I need to take in next.
