Is there a way that I can tell if the gloss finish that was used on the piano is polyester or lacquer? I'm trying to determine the best way to care for it.
The best way to tell is to scratch it or sand it someplace inconspicuous and smell
the powder. Freshly sanded/abraded polyester will have a distinct smell of styrene. If it smells like styrene then it's polyester. Nothing is easier than that.
Polyester powders white when it's sanded but so does lacquer.How to Care for Non-Polyester Surfaces
The best way to care for a non-polyester surface is to wipe it with a dampened cloth (not wet, not damp, not dry, but dampened). You can spritz water on the cloth using a plant mister (plant atomizer, spritzer bottle).
Flannel is a good cloth. These relatively new microfiber cloths are really nice. Terrycloth (beware of the stitching and labels) works well. All cotton is all good. If you use t-shirt material, beware of the stitching and it ought to be 100% cotton.
Inspect the cloth first to make sure that there's no embedded grit or dust in it. Dust scratches, it can have an abrasive quality. For that matter, so can the cloth and that's why you want it dampened. The dampness acts as a lubricant.
Once or twice a year wipe down the piano with a furniture polish. Endust is ok. Weiman's seems to be less streaky. Guardsman is streaky but it's a pleasant polish to use. Wipe with the grain and follow up with a clean cloth to try to leave no residue. Don't
use elbow grease, i.e., no downward pressure. Your job is to use the wiping cloth to pick up dust and to allow the polish to wipe away fingerprints and any grease, food, who knows what.Don't
use Liquid Gold. Don't use Lemon Oil. Your polish ought to be a foam white when sprayed out of the can. Clear polishes will leave you with an oily mess and they do little or nothing for fingerprints.
If you are going to use soapy water, Ivory bar soap is the only soap made that's pH neutral. All other soaps, all of them, are alkaline (the have pH's above 7).
To use furniture polish, spray the face of your wiping cloth. You can spray the piano, both methods work. Spraying the cloth is a tad easier.How to Care for Polyester Finishes
If you are sure that the finish is polyester, I really like Brilliantize. I think you can get this stuff on amazon.com. A little goes a long way. Flannel works great...all the wiping cloth recommendations listed above apply here.
I also like Glass Plus and yes, I use Windex. Windex contains ammonia, and apparently (according to furniture manufacturers Glass Plus does not contian ammonia). Ammonia is an alkaline and it has strong potential to break down finishes, polyester being one of the most chemically resilient finishes used on pianos. I really like the aerosol Sprayaway Glass Cleaner, find it in auto-supply stores.
To use, spray the piano and wipe until your cleaning material evaporates.Keyboard Keys
Wipe them down with a furniture polish and any tight-weave cotton cloth or the microfiber cloth. Why so? Fingers let off oil. That oil has an acidic pH. Over time your finger oils will soften the material that is your keys and you can get grime. Furniture polish will do a decent job cleaning your keys of your grimy prints. In that "slipperiness" is an issue, use the Weiman's furniture polish because it cleans off with the least amount of oily residue. Don't
use Pledge on your keys because the silicone oils in Pledge are there because
silicone oils are slippery. Eventually the oils evaporate, eventually. Pledge also has wax in it and the wax doesn't evaporate. So because of silicone oils and wax, don't use Pledge on your keys. It's the most "oliy" of all of the polishes.
Regarding silicone oils, for those of us who might polish a piano to a gloss, do not
use 3M's Fill In Glaze. That polishing material contains silicone oils.
Silicone oils are not any single oil. They are a class of low-viscosity oils, hence my pluralizing them.