"That looks like a classic case of de-zinc caused by exposing BRASS bushes and fittings to hot steam and water.
The bushes and all fittings, or at least the threaded portions of fittings, should be made from BRONZE."
I have many 50-70 yr. old Jensen's with all Brass boilers and threads as well , with no signs of erosion and very little wear , am I missing something ?