It is usually done with dilute household bleach, to kill bacteria and fungi primarily but also animal pests I suppose. Look up dilution and timing instructions by googling > disinfecting cuttings

Crab grass does not regrow from a few bits of root left in the soil, but it will grow from seeds that are in that soil. If you burned Crab grass with a torch it would not regrow, although if there were seeds in the soil they may well germinate. Crab grass is an annual thaqt produces one plant per seed and that one plant when killed is dead. If you did have new growth from any roots left in the soil or if a plant did regrow after being torched then you do not have Crab grass.

Most double-acting baking powders contain both cream of tartar and an aluminum salt (along with the sodium bicarbonate). The former works at room temperature. The latter only at oven temperature. Rumford baking powder substitutes monocalcium phosphate for both the cream of tartar and the aluminum salt. It works just like regular double-acting baking powder at room temperature but it rises less in the oven. It's sort of halfway between single-acting and double-acting in that respect. I use it because I think that the regular double-acting has a nasty taste. --Doug

I have been a metalsmith since 1988. It's not a "job", I don't work for someone else. I have an MFA in Jewelry and Metals, earned in 2006. As part of my training we studied forging, welding, casting and fabrication from sheet metal: in copper, brass, bronze, nickel, and silver. Including blacksmithing in iron. NO PIECE was considered complete until a proper PATINA was created. It is an important part of the finishing process, whether through application of chemicals from a bottle, liver of sulphur, fuming with ammonia, etc. Though it it IS an important part of the work, it is still an APPLIED patina. Here is the definitive book on the subject, which I and every other metals student studied : https://www.amazon.com/Colouring-Bronzing-Patination-Metals/dp/0823007626 Oxidation is nothing more than a chemical reaction between the molecules in the metal and compounds in the air (as in your outdoor bronze example) or compounds applied, such as the sulphur released by a liver of sulphur solution. A microscopic layer forms which is technically an alloy of the metal and the chemical, such as silver sulphide. You APPLY a patina chemical. OXIDATION is the result. Calling it "artificial" ...well: it's ALL artificial. I don't know of a single sculptor or jeweler today who lets their pieces color naturally in the air. It is because you cannot control the result that way. Go to an art fair like the Des Moines Art Festival (not a craft fair with "yard art") and talk to some modern day bronze sculptors. Ask them if they let their pieces color naturally. From ancient times through the Renaissance to the present day: sculptors have colored their metals. I have seen old recipes calling for burying the piece in sawdust with urine added; akin to the ammonia fuming of today. A raw bronze is not a pretty thing. There is no contrast, no richness of the surface. No Renaissance sculptor would have thought of exhibiting one. Unless coated with lacquer, all patinas are "living" surfaces. They will continue to react and the color change with time: sometimes looking better with age, sometimes not; with the original metal gradually being eroded/penetrated by the alloy. Hence many outdoor bronzes in Italy (where acid rain and air pollition in general is a problem), have been removed indoors to controlled conditions, and copies placed outdoors. https://en.wikipedia.org/wiki/Horses_of_Saint_Mark