It has been shown that freeze-drying after pretreatment with a PEG solution is a satisfactory way of treating waterlogged wood. Under certain circumstances it is possible to prevent shrinkage with this method. Recently, the approach has been refined and two molecular weight grades of PEG are now employed. A liquid grade, such as PEG 200, is used to control the cell wall shrinkage and waxy solid PEG 3350 is added to give some structural strength to the weak wood. An important aspect of this approach, is the desire to use the minimum amount of PEG in the most effective way, and to adjust the treatment to suit the wood. Ideally, treatments should be dusted to suit each wood object. Wood density, anatomical characteristics, environmental effects, state of degradation, etc., are all factors which distinguish wooden artifacts one from another, and it is these which should determine the grade of PEG and the conditions of treatment. To adopt this approach it is necessary to carry out analysis to determine: 1) Wood species 2) the actual density of the wood. In addition it is important to know: 3) the normal density of the wood 4) the moisture content at fibre saturation point of the normal (i.e. undeteriorated wood. Simple procedures for obtaining this information have been developed, and these data are entered into a computer programme called PEGCON which calculates appropriate PEG concentrations. This programme also calculates weights and volumes for making up PEG treatment solutions. In addition it will calculate PEG concentrations according to certain other treatment regimes.