Some timber manufacturers recommend not to use an oil or wax treatment for their veneered doors. This is because an oil/wax treatments are designed to absorb into the timber and must absorb through the veneer to ensure this. During this process there is a small risk of the veneer lifting. Osmo Door Oil is a recommended finish for interior doors and is suitable for veneered wood also. For exterior doors that are fully vertical we recommend Osmo UV-Protection Oil, otherwise use Osmo Natural Oil Woodstain. We do recommend a apply a small trial application prior to use.