Research done at the Canadian Conservation Institute on the use of stabilizers in varnish formulations is summarized. The yellowing of dammar varnish can be effectively reduced with certain antioxidants, in particular Irganox 565. Similarly, changes in solubility of Ketone Resin N due to photo-oxidation and crosslinking are slowed down by the incorporation of suitable UV absorbers and antioxidants. The need for a sound, rational approach to accelerated aging techniques is discussed in light of the end-use of the materials tested. The methods used in some recent work on epoxy adhesives in the author's laboratory are summarized.