While reshafting  Mizuno 921 Hot Metal irons I found a hard gel like substance in housel and shaft. I have reshafted several other sets not Mizuno and never came across that.

steveb8 Edited comment August 31, 2022

It was white and I removed it carefully from the hosel and shaft. I reshafted one club as a test for a more flexible shaft. If I decide to do the rest of the clubs, I will order them from GolfWorks. So, I will post at that time as a follow up if they all have the white gel. Could it be an excess of a white epoxy used by Mizuno during assembly? I used a heat gun to remove shaft and within ten minutes it appeared to me as sought of rubber consistency.