Several of the companies listed in this manual offer emergency environmental control and interior drying services and are possible sources of assistance if the work cannot be done in-house or by the institution's normal maintenance and repair contractors. Another important part of building rehabilitation is cleaning of the collection spaces which have been damaged by water, dirt, soot, or other contaminants. Accumulations of dirt and soot may be vacuumed up, but it should be remembered that most vacuums do not have filters which will trap the finer particles, which will then be blown back out into the air through the exhaust. After the initial salvage work is completed and the affected parts of the collection are safely dried or frozen, much work will still remain to be done. The damaged materials will need to be cleaned, repaired, rebound, rehoused, and returned to the shelves.
Rehabilitation begins with sorting.
Sorting and Assigning Priorities Much of the work of sorting will have already been done during the salvage phase of response to a disaster. It remains for the institution to decide how many of the frozen materials must be freeze dried, and how many can be air-dried. If funds are limited, some decisions will have to be made concerning what to restore. Treatment of Water-Damaged Materials Freeze drying and vacuum drying Freeze drying is well known as a technique for salvage of waterlogged books and documents. Vacuum freeze drying is the safest method for books.