In the process of cleaning the spine of older books the outer page of many of the sections is damaged.
This needs to be repaired. Here are some simple steps that may assist.
Open out and check the level of damage.
Insert the other pages forming the section and close. Check that all the bits of glue are cleaned off the spine area and that the section pages are alligned evenly.
Prepare strips of a moisture barrier paper, we use waxed lunechon wrap from the supermarket.
Cut strips of the Japanese repair tissue (we stock this paper and it is quite inexpensive per sheet). These should be longer than the section to allow you to hang on to either end and position it with ease.
Place the repair tissue onto some waste paper and, using paste that is not too thick, past out the strip just leaving the 2 ends dry.
Place the pasted tissue on the strip of waxed paper, pasted side uppermost of course.
Carefully place the section on the pasted repair tissue. Allow a little more than half the pasted tissue ready to pull over the section.
Simply pull over the wax paper and this pulls over tightly the pasted repair tissue. The waxed paper remains around the section protecting it from the moisture involved.
The repaired sections should be placed under pressing boards, under a fairly light weight until dry.
When dry you simply discard the wax paper, use your blade to trim the overhanging pieces of Japanese repair tissue, and prepare to sew your text block.
Please let me know if this is of any assistance to you.
It is a step we take many times when repairing to rebind an old book.