I have quite a few 400 type KTUs as backup to my 1A2 system. Each KTU is bubble wrapped, and stored horizontal (as they would be installed). They are kept in an air conditioned area. I have found the same leaky green goo from a small percentage over the years, and it is easily removable with no apparent damage to the KTU. While I have other KTUs (e.g. Manual Intercom, Power Failure, Tie line, etc), the 400 D is the only one I have found the green leakage on.
