The first step is to dismantle the volume. This is done by cutting the endpaper near the inner edge of the cover to gain access to the spine. Subsequently, the leather spine is separated from the bookblock. A bone folder or spatula is used to loosen the skin from the spine. Afterwards, the binding thread is cut, and the pages are detached from the book using the same tools to separate the spine from the bookblock.

The old glue is removed once the sheets of paper are detached from the book. This is done mechanically by scraping off the dry glue using various spatulas.

Different damages are marked, and the sheets of paper are arranged in fascicles. These fascicles are made of acid-free, archival standard paper and then stored in custom-sized boxes made of acid-free cardboard.

The damages on the documents are repaired using Japanese paper of the kozo type, a strong paper with long fibers, and an adhesive made from wheat starch. Before the repairs are made, the area around the damages is dry cleaned with a soot sponge to prevent dirt from reacting with the moist paste and causing stains. The Japanese paper is torn into strips adapted to the shape of the damages. The tearing is done to create repair pieces with an uneven edge that is gentler on the documents. After the repairs are made, they are left to dry under weight with a blotting paper. The most common damages to the documents in the Gustavian collection are tears, torn joints, hinges and folds, and curled brittle edges.

Tears are repaired with a strip of Japanese paper pasted to the back of the documents. The strips are placed so that no text is covered. Tears usually occur in folds that were made before the documents were bound into a volume.

The entire or parts of the folds may be damaged by the old glue or binding thread. This makes it challenging to handle the documents without risking the two leaves coming apart. Repairs are made on the inside of the sheet’s fold with Japanese paper and adhesive. If there are major damages to the fold, tissue, a thin Japanese paper, also of kozo, may be adhered to the outside of the spine.

In volumes where there is a wide variation in the size of the documents, there are many damaged edges. The edges are very brittle, and it is not uncommon for parts of the edges to have already come off. The first step is to flatten the edges—they are unrolled and laid flat before weight is applied. In difficult cases, the edges are moistened with a mixture of ethanol and water. After that, the documents lie under weight until the edges retain their correct shape. Larger tears are repaired in the same way as mentioned earlier. Brittle areas or areas with many small tears very close together are consolidated with a larger piece of tissue  pasted to the back of the document.

Most of the described damages are repaired by a bookbinder, while a paper conservator repairs more extensive damages. Two other recurring actions performed by a paper conservator are actions on old repairs and the dismantling of two or more documents pasted together, where text may be obscured.

The collection has been heavily used and repaired over the years. Not all previous repairs have been done in a way that is beneficial for the material. If a repair is inadequate by today’s standards, it is removed, and the damage is repaired with materials and methods that are better suited.

Some documents were added to the collection later. These new documents were pasted onto an already existing document in the volume. No action is needed if the new document is securely attached and does not cover any text on the old letter. Unfortunately, they are usually glued in a way that covers the text on the other document. In those cases, a methylcellulose solution in water is used locally to dissolve the adhesive. In severe cases, it may be necessary to immerse the entire letter in water or a mixture of ethanol and water (depending on what the text can withstand) to dissolve all the adhesive and separate the documents.