Thomas Jefferson obtained a varnish recipe from Gilbert Stuart. There is no documentation that he actually used the varnish on his furniture, but he did copy the recipe in his own hand. Jefferson's written version of the recipe is held at the Library of Congress.1 A transcription is provided below.
A varnish for mahogany furniture from Gilbert Stuart
boiled linseed oil spirits of turpentine (in equal parts) add 1/6 part of wax. warm the whole in a gentle heat, to about the consistence of butter in hot weather. rub it on the furniture with a woollen cloth. it cannot be sat in the same day. requires renewing, perhaps once a quarter.