Thomas Jefferson obtained a varnish recipe from Gilbert Stuart, but we do not have any documentation that he actually used the varnish on his furniture. The recipe can be seen in Jefferson's own hand on the Library of Congress website. A transcription is 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.