Cleaning Kerosene/Paraffin Lamps
I have often mentioned that lamps found on eBay and bought at auction are often in a miserable condition. They are dirty, the brass or bronze parts are heavily tarnished, the bronze-finish on the zinc parts has become dull or even almost completely rubbed off, the burners are often dented and resinous, at least darkened, the wick knob is not functional, etc. Lamps bought in good antique shops and auction houses are naturally clean and well cared for; further cleaning is not absolutely necessary with them. However, the question of "patina preservation" also arises with these lamps. I will return to this subject later.
Since I have assembled my collection to date largely from eBay finds and consequently have almost always had to carry out cleaning and repair work, I would like to pass on my experience in this subject here.
But something very important first:
In this and also in the next chapter (= Repairs), I will name the implements and materials that I think work very well by their trade name. This is done completely without advertising purposes. I have never received any money or other benefits from the companies that produce these tools and materials, nor do I intend to have my recommendations subsidised in any way in the future. If, after years of experience, I am of the opinion that product X from company Y is very well suited to a job to be done, then I am happy to say so, but without ulterior motives. I think other people should also benefit from this accumulated experience. But that also happens without a guarantee. Everyone should try out for themselves whether a product I praise or a procedure I recommend is also suitable for their purposes. I do not recommend anything that has not worked well for me. However, I give no guarantee that it will work just as well for other people without causing any damage.
Lamps always consist of glass, ceramic, stone and metal parts (apart from wooden bases of sculpture lamps). Depending on their state of preservation, they are slightly or more heavily soiled and need to be cleaned.
The first step in cleaning a lamp is to disassemble it properly: you have to take apart all the separable parts to clean them separately. This is where a problem often arises: Many lamp parts are connected to each other by a threaded rod that is screwed tightly with a nut at the bottom. The screwed threaded rod gives the lamp vertical stability and sturdiness. This threaded rod is almost always made of iron. Depending on the age of the lamp, it and the nut at the bottom may be so rusty that they cannot be unscrewed even by force. It has been my experience that common rust removers fail because the rust is often very pervasive. In such cases, I cut the rusted nut with the fine cutting disc of my hand drill (Proxxon® or Dremel®). It is true that with this step the threaded rod is shortened at the bottom and therefore no longer usable; but you can replace it completely with a new threaded rod. If possible, you should use new threaded rods and nuts made of brass to avoid the annoying rusting. These replacements are available in various thread sizes at hardware stores. The original nut soldered to the font made of sheet metal must also be removed for this and replaced with a new nut, as the threads of yesteryear are not compatible with the standardised threads of today. Some manual skill is required.
The lamps with a threaded rod often have an iron plate at the bottom to fix the metal base to the threaded rod. This sheet metal is almost always rusted on the surface. I remove the rust as thoroughly as possible with suitable abrasive brushes. Then I treat the bare iron surface with a rust converter and paint the sheet metal on both sides with black paint to prevent further rusting.
My tip: Only superficially rusted iron parts can be easily derusted in citric acid. Citric acid is available in granular form from mail-order companies. Place the parts to be derusted in a moderately concentrated citric acid (approx. 20% in water) and allow the acid to take effect. The duration of treatment depends on the concentration of the acid and the thickness of the rust layer. After cleaning and rinsing the parts well with water, they must be protected from rusting again with a protective lacquer.
Caution is always necessary when taking lamps apart. Especially the longer column lamps often have several individual parts to assemble the base and the column alone. It is always advisable to record the correct order of these parts. Often many days, even weeks, pass between disassembly and reassembly, depending on the extent of the cleaning and repair, and then one no longer knows the correct order.