Vivid Ready

Soap from scratch: rainwater dripped through hardwood ash = lye water (floats an egg = right strength) + any fat/tallow, simmered and cured. Soap is civilisation; this closes the hygiene loop forever.
Candles & tallow lamps: rendered fat or stockpiled wax + braided cotton wicks; a tuna-tin tallow lamp is an hour's work.
Charcoal making: wood in a sealed drum with small vents, cooked in a fire → charcoal for filtration (B1), forge fuel, drawing, and cleaner cooking.
Salt from seawater (coastal): boil/evaporate in wide pans; ~35 g per litre. Inland: know your nearest historical salt source — seriously, wars were fought over it.
Sewing & repair as a real skill: patching, darning socks, replacing zips, resoling with tyre rubber. Stock heavy thread, awl, wax. Clothing durability doubles.
Tanning (ambitious): egg/brain-tan or bark-tan small hides → leather for repairs. Deep Phase 3, but the reference belongs in the vault.
Alcohol & vinegar ferments: wild-yeast fruit ferments → country wine → vinegar (leave it open with a mother). Antiseptic, preservative, morale, premier barter. (Distillation is illegal many places — know your law.)
Ash, bones, nothing wasted: wood ash = lye, tooth powder, garden lime-ish amendment, chicken dust baths; bones = stock (nutrition), then charred = bone char filtration/fertiliser.

The parent page is the closed-loop chapter and it is the most enjoyable in the playbook. Three of its entries carry risks or costs the summary cannot fit, and one of them is a criminal offence.

Lye is the dangerous one

Soap from wood ash is the crown of the Phase 3 chapter and it is the single most dangerous thing described in this app.

DANGER

Lye causes severe chemical burns and permanent blindness. It does not hurt immediately, which is why people keep working with it on their skin.

Wood ash lye is potassium hydroxide at an unknown, variable concentration. Every batch differs with the wood, the ash and the water. There is no way to know its strength by looking.

The floating egg test is a folk method, not a measurement. It tells you the liquid is roughly dense enough. It cannot distinguish safe-ish from far too strong, and the margin it appears to give is not real.

If you do this:

Goggles, not glasses. Splashes go sideways and upward.
Long gloves, long sleeves, closed shoes, apron.
Outdoors, upwind, with nobody else nearby and no children or animals.
Add lye to water, never water to lye, and never into hot liquid.
A large container of clean water within reach at all times. Flush any splash for a long time, longer than feels necessary, and get medical help for any eye contact without waiting to see whether it settles.
Stainless steel, glass or heavy plastic only. Never aluminium, which reacts violently.

Expect soft soap, not bars. Wood ash gives potassium hydroxide, which makes a soft or liquid soap. Hard bars need sodium hydroxide, which is bought rather than made.

This is not a beginner's craft and it is not one to learn under pressure. Learn it, if you want to, on a calm afternoon with proper protection, years before it matters. Meanwhile, soap is one of the cheapest things in the shop and the budget page says to buy far more of it than feels sensible.

What sea salt actually costs

The parent page gives the right figure and the consequence is worth doing.

Seawater is roughly 35 grams of salt per litre. So a kilogram of salt means evaporating about 28 litres of seawater, and if that evaporation is done by boiling rather than by sun and wind, the fuel bill is enormous. It is one of the least efficient uses of firewood in the entire app.

Which puts it in perspective:

Buy salt now, by the kilogram. It costs almost nothing, it stores forever, and the food chapter already tells you to hold several kilos. This is the answer for any realistic disruption.
Solar and wind evaporation in shallow pans is the sensible method where the climate allows, and Britain's climate mostly does not.
Boiling is a last resort, and worth knowing rather than planning around.
Coastal water quality matters. Estuaries, outfalls and harbours are not where to collect, and after heavy rain is not when.

The parent page's real point stands: know where your nearest historical salt source is, because salt is genuinely irreplaceable for preserving. That is a piece of local knowledge worth having, and it belongs on the map with everything else.

Distilling is a criminal offence here

The parent page says distillation is illegal many places and to know your law. In the UK the answer is unambiguous.

Distilling spirits without authorisation from HM Revenue and Customs is a criminal offence, at any scale, including for personal use, including if you never sell a drop. Owning a still without authorisation is itself regulated.

Brewing and winemaking at home are lawful, for personal consumption. So is making vinegar. The line falls at distillation.

Which is convenient, because the useful outputs are on the legal side:

Country wine from a wild-yeast fruit ferment, which is the parent page's own suggestion and is lawful.
Vinegar from that wine, left covered against insects but open to the air, because the mother needs oxygen. Preservation, cleaning, pickling and a genuine antiseptic.
Beer and cider, which are calories, morale and barter.

Alcohol as a wound antiseptic is overrated anyway. Clean water and soap do the job, per the wound care companion, and drinkable-strength alcohol is a poor disinfectant. This removes most of the argument for wanting a still.

The crafts worth learning first

Ranked by how soon they pay off, rather than by how deep into Phase 3 they sit.

Sewing and repair. The parent page is right that this doubles clothing life, and it is the only craft here you will use this month. Patching, darning, a zip, a button, a hem.
Fermenting. Sauerkraut needs a cabbage, salt and a jar, works first time, preserves food and makes vitamins.
Vinegar from a mother. Nearly free, self-sustaining, endlessly useful.
Candles and tallow lamps. An hour's work, immediate result, and it uses fat that would be thrown away.
Charcoal. Genuinely useful for filtration and cooking, and see the caution below.
Soap from bought lye, learning the process safely, before ever attempting ash lye.
Tanning, which is slow, unpleasant, and belongs exactly where the parent page puts it, which is in the reference vault rather than on the calendar.

Nothing wasted, honestly

The parent page's last entry is the philosophical one and it is true, with one correction worth making.

Wood ash genuinely is useful: lye, a mild abrasive, a chicken dust bath, and a soil amendment. It is not lime, though, and it should not be spread as though it were. It raises pH and adds potassium, and it is easy to overdo on a small plot. Use it sparingly, and not around acid-loving plants.

Bones are excellent stock and the nutrition case for them is real. Charred bone as filtration material is a genuine historical technique and is well down the list of things a household needs.

The principle underneath all of it is the one to keep: in Phase 3 the question stops being what to buy and becomes what a thing can be used for next. That is a habit rather than a craft, it costs nothing to start, and it is the actual content of this chapter.

Phase-3 crafts