Old tarred surfaces can be restored by cleaning away loose dirt and failing material, checking the timber underneath, and applying a compatible fresh coat only where the surface can accept it.
An old tarred surface may look dull, cracked, grey, glossy in patches, dusty, or uneven. That does not always mean it has failed. The first job is to decide whether the old coating is still bonded or whether it is peeling, trapping damp, or hiding damaged wood.
Clean gently before recoating. Remove loose flakes, algae, soil, and powdery surface material without stripping sound old tar unnecessarily. If the wood beneath is soft, rotten, wet, or badly split, repair comes before finish. Fresh tar over failed wood only makes the problem darker.
Use a compatible tar or pine tar finish and apply it thinly into dry exposed areas. Restoration usually looks best when it respects the old surface rather than burying it under a thick shiny coat. The aim is to renew protection while keeping the texture and age of the object visible.