removing lead paint from wrought iron
I know this may be a little longer than you might want but it is rather important.

Short answer - Use a heat gun and mineral spirits.



Removing Paint from Wrought Iron, Cast Iron and Steel Using Thermal Methods

This specification provides guidance on the selection of appropriate thermal methods of paint and rust removal from wrought iron, cast iron and steel. These metals should be repainted immediately following paint removal in order to prevent exposure to the atmosphere and subsequent corrosion.

Thermal methods as used herein shall apply to high velocity oxy acetylene or oxy propane flame cleaning, a standard surface preparation method for steel and cast iron, or to the heat gun.


The heat gun works using a hot blast of air at 500 to 750 degrees Fahrenheit. Extreme caution should be taken when using this method.
Heat higher than 1100 degrees Fahrenheit will vaporize lead paint and is hazardous.
The hot air blast produced by the heat gun can ignite debris within a wall cavity or behind a cornice or soffit. The dust can smolder only to ignite hours later after the work crew has gone home so extreme caution must be taken when using this method.
As with flame cleaning, the hot air of a heat gun can overheat cast iron and steel features creating localized thermal stresses, or causing small sections to become distorted.




There are several causes for paint failure on metal. 


Excess moisture can cause rusting. As metal rusts, the rust expands breaking the bond between the metal and the paint. 
Inadequate or improper surface preparation can interfere with the proper bonding of the new paint. The wrong primer can cause anything from pitting of the metal surface to peeling of the new paint.


It is not necessary to remove all previous coats of paint if:


They are adhering soundly.
The new painting system is compatible.
Important design details are not being obscured by the paint layers.


Chemical products are sometimes sold under a common name. 

This usually means that the substance is not as pure as the same chemical sold under its chemical name. The grade of purity of common name substances, however, is usually adequate for stain removal work, and these products should be purchased when available, as they tend to be less expensive. Common names are indicated below by an asterisk (*).

Mineral Spirits:


A petroleum distillate that is used especially as a paint or varnish thinner.
Other chemical or common names include Benzine* (not Benzene); Naphtha*; Petroleum spirits*; Solvent naphtha*.
Potential Hazards: TOXIC AND FLAMMABLE.
AVOID REPEATED OR PROLONGED SKIN CONTACT.
ALWAYS wear rubber gloves when handling mineral spirits.
If any chemical is splashed onto the skin, wash immediately with soap and water.


Available from construction specialties distributor, hardware store, paint store, or printer's supply distributor.



Here is a video link on YT for removing paint off metal 
Stripping paint with heat gun 1965 Mustang