Tar can be used on handcrafted boxes as an exterior dark finish, especially for rustic, historical, outdoor, or display boxes, while the interior is usually left clean or finished separately.
A tarred box has a strong character. It can look maritime, medieval, Scandinavian, or simply old and practical. Pine tar suits tool boxes, reenactment chests, outdoor storage boxes, seed boxes, and display pieces. It is less suitable for jewellery boxes, book boxes, or anything that must smell clean inside.
Apply tar to the outside after construction and surface preparation. Use a cloth or small brush and keep the coat thin around hinges, lids, catches, and handles. Tar can creep into moving parts and make them unpleasant to touch. The bottom and corners can take more treatment because they see more wear.
The inside of the box should be considered separately. If tar is used inside, the smell and staining can affect anything stored there. For most craft boxes, a tarred exterior with a clean dry interior is the more useful combination.