A method of treating waterlogged leather based on the work published by m. Carlsson but with some modifications (indicated in the text). The practical work was carried out in denmark on 50 leather objects, excavated from a wet-side medieval leather workshop. The leather pieces were first washed in deionised, distilled water, then cleaned in a bath of 37.2 g. Edta in 1 litre water, buffered to ph 5.5 - 6.0 with ammonium acetate, using ultrasonics for part of the time. This bath was repeated, followed by 4 rinses in water, also with ultrasonics to increase removal of iron-containing soil and edta. (oakite, a mixture of orthophosphoric acid and corrosion inhibitors, subsequently replaced the edta. The leather was then dehydrated, first in 1:1 ethanol: acetone, then 100% acetone, before impregnation with bavon asak abp at 15% v/v acetone. Drying under boards helps prevent shrinking. 3-dimensional objects are humidified for a short period, before stuffing with acid-free tissue to shape. Bavon, containing o-phenylphenol, is painted on surface.