The main objective is to remove all of the rust and paint and stabilize the metal to prevent further deterioration.  You should have some basic knowledge of working with chemicals before attempting the following procedures.   These are only basic guidelines, but they will give you a starting point to develop your own system. WARNING: Sand blasting or glass bead blasting will not only remove the patina but is the fastest way to destroy the value of a lantern, and possibly blast holes through the metal.      (NOTE:  Take all safety precautions, use gloves, safety glasses, etc.) PH-Down (Sodium Bisulfate) Method  (PREFERRED) This method will remove rust, crud, (and eventually paint) without removing the patina. 1.  Remove the fuel cap, globe, and burner from the lantern. 2.  Mix 1 cup of PH-Down in Warm Water in a sealable 5 to 10 gallon plastic container. 3.  Submerge the lantern and burner *entirely in the Solution for **1 day. 4.  Remove the lantern, and lightly scour with a Brillo pad, (not SOS,) 5.  Repeat steps 3 and 4 until all the rust or tarnish has been removed. 6.  Once you are finished, give the lantern one final rinse in the solution, then dry with paper towels immediately.  Use a blow dryer on low to dry the inside of the tank. 7.  After the lantern has been cleaned,  I recommend polishing it first with Blue Magic (tm) Metal Polish to bring out the luster. You can also use #0000 steel wool to buff out the lantern. 8.  To finish the lantern ***paint or lacquer it with your choice of finish.  If using paint, taping off the center air tube on hot blast lanterns, or the chimney on cold blast lanterns, makes for a professional, like factory, looking job.  If the filler spout is brass, you might also tape it off as well.  This also goes for brass wire guides and lift brackets as well.  The burner cone and burner should be left unfinished.  An alternative to painting tin plated lanterns is to wipe them down with a small amount of boiled linseed oil mixed 50:50 with kerosene. Molasses Method  (PREFERRED) This method will remove rust, crud, (and eventually paint) without removing the patina. 1.  Remove the fuel cap, globe, and burner from the lantern. 2.  Mix 12 oz. of Grandma's Molasses in Warm Water in a seal-able 5 to 10 gallon plastic container. 3.  Submerge the lantern and burner *entirely in the Solution for **1 day. 4.  Remove the lantern, and lightly scour with a Brillo pad, (not SOS,) 5.  Repeat steps 3 and 4 until all the rust or tarnish has been removed. 6.  Once you are finished, give the lantern one final rinse in the solution, then dry with paper towels immediately.  Use a blow dryer on low to dry the inside of the tank. 7.  After the lantern has been cleaned,  I recommend polishing it first with Blue Magic (tm) Metal Polish to bring out the luster. You can also use #0000 steel wool to buff out the lantern. 8.  To finish the lantern ***paint or lacquer it with your choice of finish.  If using paint, taping off the center air tube on hot blast lanterns, or the chimney on cold blast lanterns, makes for a professional, like factory, looking job.  If the filler spout is brass, you might also tape it off as well.  This also goes for brass wire guides and lift brackets as well.  The burner cone and burner should be left unfinished.  An alternative to painting tin plated lanterns is to wipe them down with a small amount of boiled linseed oil mixed 50:50 with kerosene. Soda Ash and Battery Charger Method  (PREFERRED) (NOTE:  THIS METHOD PRODUCES HYDROGEN. CONDUCT ONLY IN A WELL VENTILATED AREA AND AWAY FROM SPARK OR FLAME) This method will remove rust, crud, and paint without removing the patina. 1.  Remove the fuel cap, globe, and burner from the lantern. 2.  Mix 1/4 cup of Soda Ash (Sodium Carbonate, NOT Sodium Bi-Carbonate) in 5 gallons of Warm Water in a plastic container. 3.  Connect the positive (red,) lead clamp of a 12 volt battery charger to an Anode, (a piece of rebar or plain iron,) and submerge the Anode (not the clamp,) in the soda ash water solution along the side of the plastic container. 4.  Connect the negative (black,) lead of the 12 volt battery charger to the lantern. (A leader wire can be used to attach to the lantern.) 5.  Submerge the lantern *entirely in the Solution for **1 day, making sure it does not touch the Anode and short the circuit. 6.  Turn on the battery charger and set to 5 to 10 amps charge for 24 hours 7.  Remove the lantern after 24 hours, and lightly scour with a Brillo pad, (not SOS.) 5.  Repeat steps 4 through 7 until the lantern is cleaned and suitable for finishing. 6.  Once you are finished, give the lantern one final rinse in the solution, then dry with paper towels immediately.  Use a blow dryer on low to dry the inside of the tank. 7.  After the lantern has been cleaned,  I recommend polishing it first with Blue Magic (tm) Metal Polish to bring out the luster.  You can also use #0000 steel wool to buff out the lantern. 8.  To finish the lantern ***paint or lacquer it with your choice of finish.  If using paint, taping off the center air tube on hot blast lanterns, or the chimney on cold blast lanterns, makes for a professional, like factory, looking job.  If the filler spout is brass, you might also tape it off as well.  This also goes for brass wire guides and lift brackets as well.  The burner cone and burner should be left unfinished.  An alternative to painting tin plated lanterns is to wipe them down with a small amount of boiled linseed oil. Lye and Vinegar Method (LEAST PREFERRED) (NOTE:  Take all safety precautions, use gloves, safety glasses, etc.) This method will remove paint and rust without removing the patina. 1.  Remove the fuel cap, globe, burner, (and aluminum reflector if any,) from the lantern. 2.  Mix 1LB of Red Devil Lye, (from your grocery store) in Warm Water in a seal-able 5 to 10 gallon plastic container. 3.  Submerge the lantern and burner *entirely in the Lye Solution for **1 day. 4.  Remove the lantern, and rinse with water, then quickly dry with paper towels. 5.  Coat with WD40 and use #00 steel wool to remove the majority of the remaining paint. 6.  Submerge the lantern and burner *entirely in a 50/50 solution of white vinegar and water for **1 day. 7.  Remove the lantern and parts and use #000 steel wool to clean off the rust and any remaining paint.  Use the vinegar to occasionally rinse the lantern while you are working on it. 8.  Once you are finished, give the lantern one final rinse with vinegar, then dry with paper towels immediately.  Use a blow dryer on low to dry the inside of the tank. 9.  After the lantern has been cleaned,  I recommend polishing it first with Blue Magic (tm) Metal Polish to bring out the lustre. 10.  To finish the lantern, ***paint or lacquer it with your choice of finish.  If using paint, taping off the center air tube on hot blast lanterns, or the chimney on cold blast lanterns, makes for a professional, like factory, looking job.  If the filler spout is brass, you might also tape it off as well.  This also goes for brass wire guides and lift brackets as well.  The burner cone and burner should be left unfinished.  An alternative to painting tin plated lanterns is to wipe them down with a small amount of boiled linseed oil mixed 50:50 with kerosene. *   Make sure that the lantern is submerged entirely or surface pitting will occur ** Pitting will occur at some point after 1 day.  Monitor closely if you leave the lantern in longer than 1 day. ***Regular spray paint works fine, (high heat paint isn't necessary) Never place aluminum in Lye solution, it will dissolve it. These processes may weaken the soldered joints, making re-soldering necessary.  I recommend using Harris brand Stay-Clean liquid flux, and Radio Shack .064 60/40 Rosin Core Solder with a micro butane torch.  (Regular plumbers propane torches yield no control over where the heat is applied, and as such are only good for de-soldering lanterns, not making repairs.) If cleaning the lantern exposes weak spots in the tank, creating pinholes, use the tank sealing method below.  Soldering pinholes is not the best solution, as more holes are bound to develop.