Before applying varnish to oiled wood, it is important to take some precautions. Oil recipes vary among manufacturers, which can make some incompatible with quality varnishes or lacquers. In particular, wax is an ingredient that should never be present in an oil that will be varnished, as it is completely incompatible with varnishes and lacquers.

Before starting your varnishing project, it is crucial to ensure that the oil present on the wood does not contain wax. If you are not sure, you can perform a test by applying a coat of varnish to an inconspicuous part of the oiled surface, waiting 3 hours, and then applying a packing tape used for package sealing to the surface, making sure it is perfectly adhered to the surface. After 5 minutes, vigorously remove the tape from the surface. If the varnish remains stuck to the tape, this may indicate the presence of wax in the oil, and you should avoid applying varnish to this oiled wood.

Note that the Prato-Verde Oils such as Uno, Secondo, Secondo Mono, and Brio, Bona Craft 2K oil, as well as Linseed oil and Tung Oil, do not contain waxes and can be varnished without any issue.