Abstract: Method and apparatus for removing paraffin deposits from the production tubing of an oil well. A sub is series connected into the production string at a location below the area where deposition of paraffin occurs, and treatment fluid, such as hot water, is pumped downhole towards the inlet end of the string. A spring loaded valve means is located in a lateral flow passageway of the sub and opens when a pre-set tubing pressure is exceeded, thereby enabling the treatment fluid to be forced down the upper production tubing, past the paraffinic deposition, into the sub, through the lateral flow passageway, and into the casing annulus, thereby dissolving the crystalline paraffin so that the production tubing is no longer obstructed with paraffinic deposits.