My observations:
Wash the whole item, concentrating on the solder lines.
Use small brush such as a toothbrush.
Avoid ammonia as it creates the possibility of residue.
Whiting/calcium carbonate rubbed over whole project will effectively clean as it is a very mild abrasive. It is not good at cleaning acids from under solder though.
Baking soda – there is some fear of scratching, but in solution there should be no granules. It bubbles in the presence of acids, so there is a visual indication of the presence of acid. But make sure you get it all off the project before applying patina. as it is alkaline, and tends to neutralise the acidic patina.
Use of an abrasive like fine steel wool, or to prevent transfer or metal, a kitchen scouring pad on the solder to help with a smooth application of the patina.
Waxing is usually done after the patina application.
Application of the patina is best done with gentle, light pressure from brush, sponge, cotton buds or rag. Allow time to react with the solder it is a gradual chemical reaction.
Buffing or polishing the patina is to be done after it is dry, using light pressure to avoid rubbing the patina off.
Waxing will polish the patina as well as protect it from oxidisation.
Note that patinas are acids specific to various metals, so black for zinc is different from that for solder and lead, and both are different from each other.
Patinas will get darker with time.
More Details
The application of patina to solder and other metals consists of three stages:
cleaning,
application,
protection.
Cleaning
Flux residues and other contaminants are left after soldering. Cleaning can be a combination of cleaning with abrasives and alkaline materials. After soldering, cleaning and drying your piece, use fine (000) or extra fine (0000) steel wool and a brass wire brush to go over all the beads. Use a brush first if you want, and follow with the steel wool, since it will provide fewer scratches. This helps remove any leftover flux that on solder lines. Some advise metal abrasives as residues can be left. However the plastic abrasive pads used in scrubbing pots can be used to finish the cleaning without leaving metallic residues.
Omitting this step increases the chances of developing whitish blotches later on the solder lines. Including this step also makes a better base for applying the patina. After using the steel wool, use a soft brush to remove any residues from the steel wool, brush, flux or solder. Baking soda – sodium carbonate – can be used to neutralise any of the acidic flux left. It bubbles in the presence of acid, giving a visual check for any acid left. It is important to rinse the baking soda off with plenty of clean water.
After cleaning the solder beads, wash the panel off with warm water and a little dish washing liquid to remove oils and other residues. When washing use a very soft scrubbing brush to get in all the little crannies.
Dry the piece with a soft towel. If the piece is framed in zinc, make sure that any trapped water is eliminated and the piece is entirely dry. Often letting it stand overnight will be sufficient. A panel with no moisture will help the polish be more even.
Apply the Patina
As patinas work by chemical reaction, they are specific to various metals. Those designed for solder react with the tin mainly, those for lead react with lead, and those for zinc react with zinc. Although each of these may work with other metals, they work best with the metal they are designed for. Too much rubbing while the patina is wet simply interferes with the action of the acid. Application of enough patina to allow it to "soak" - actually time to react with the metal - is much better than rubbing. It is a chemical reaction, not a buffing process.
Pour a small amount of the patina into a small container so as not to contaminate the rest of your patina. Do not pour the remainder back into the bottle, as it will begin to neutralise the main supply. Apply your patina with a small flux brush reserved for the purpose, or a piece of a rag. If you use a rag, renew it frequently. Do not be afraid of putting too much on. If you are not happy with the colour when dry, you can rub the solder over with a 400 (also known as 000) wire wool or an abrasive scrubbing pad to abrade the surface. Then give it a further coat.
Once the patina is dry, you can use the baking soda solution again to neutralise the remaining acid on the metal, but it is not absolutely required.. Rinse well, and rub gently with a dry cloth to assist the drying, do not scrub. When dry again you can re-wax the metal.
Sometimes a white residue appears alongside the solder bead after a piece is finished, covered in patina, and waxed. This seems to have two causes.
Residual acid
As there is a possibility of some acid remaining on the piece, rinse with a bit of bicarbonate of soda added to the water. This will neutralise the acids from the flux and patina that may still be lurking under the foil and solder beads. If you get a frothing while cleaning with the soda, you will know there is still acid present. Wash - rather than scrub - those areas again with the water and soda solution until there is no foaming.
Trapped moisture
Moisture can also produce this white residue, as it allows minerals to migrate from under the solder seams. The advice centres on cleaning. Do not use much soap in the initial cleaning solution. After rinsing ensure the piece is completely dry by setting it aside in a warm dry place for a day or two before waxing or sealing.
Preservation
To preserve the desired finish, a coat of beeswax, carnuba, or other car wax helps, but remember that copper will oxidise over time no matter what you do. It is this what gives it a rich deep antique lustre.
Some allow the waxed piece to sit for 24 hours and then re-wax it. The applicator should be a soft object such as a cotton bud or soft cloth. Do not polish it until it no longer is showing black or copper. Rather allow it to sit undisturbed for several days. The patina will get darker and smoother over time. Don't worry too much about getting it pitch black, or bright copper the first day.
Those that use paste waxes seem to have less difficulty than those who use thin or spray on waxes. The heavier waxes seem to seal any moisture within the structure. The moisture seems to be able to migrate through the thinner waxes. Still, it is not optimum to have moisture sealed within the panel, as it will eventually come through the wax as it ages. It seems the best long term result will be achieved by ensuring everything is absolutely acid free and completely dry before waxing.
Use a good quality furniture polish or wax. Shake the bottle well if it is a liquid, then apply liberally to a soft cloth, or good quality paper towel, rubbing all over solder. If you have a glass with a deep texture, try to avoid this all over process, as it can be hard sometimes to remove all of the polish from th edepth of the undulations afterwards, and it is noticeable when it dries. Alternatively, mask off the glass from the solder.
Immediately after applying the polish, take a clean, dry soft cloth or new paper towel, and begin to gently rub the solder seams. If you are using paper towels, you will need a lot of them, as they tear up quickly. When both top and bottom sides have been polished, check for any missed spots, especially along the edges of your solder seams. Also check for polish residue in tight corners and along the edge of the solder. An old toothbrush often works to remove it. If you need stiffer bristles, make sure you keep this new toothbrush separate from all the others in the house.
Observing these methods should provide long lasting patinaed pieces.
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