制硝矾法。别名玉丹，又名雪霜。先用生矾一两打碎如豆大，入银罐，内入炉，用桴炭
火
烊，以食箸刺入罐底，搅之无块为妙。次将上好硝三钱打小块投下，约十分之三。再次将白
硼砂三钱打碎投下，亦十分之三，少顷再投入生矾，逐渐投下，候烊尽。照前投硝、硼少许
，如是逐渐投完，直待浦起罐口，发如馒头样，方可加起炭火，烧至干枯。然后用净瓦一大
张，覆罐口一时取起，将牛黄少许为细末，用清水五六匙调和，以匙超滴丹上，将罐仍入火
内烘干，即取起，连罐覆洁净地上，先以纸衬地，罐上仍用碗覆之，过七日，收贮听用。须
轻松无监纹者佳，如有监纹者不堪用，或留作蜜调用，亦好算敷药。 时初起火宜缓，然亦
不可太缓，恐致矾僵，定难溶化，后必监实有纹，中间及后，须用武火，又加矾末烊尽，即
投硝、硼，必不能全化，以致坚实有纹矣。须用倾过之旧罐，取其入炉不爆碎也，如用新罐
先将炭烘过，然后入炉，亦不可放湿炭上烘，使湿气入罐，经火必碎。又说倾银过之罐，恐
犹有毒瓦斯。此丹宜制备，愈久愈妙。
须烧茅柴者，谓之百草霜。取其近底者，锅心及锅口边，俱不可用。先刮去浮面一层，
后刮去中一层，不可重刮，盖着锅第三层，又不堪用。
制硝矾法。别名玉丹，又名雪霜。先用生矾一两打碎如豆大，入银罐，内入炉，用桴炭火烊，以食箸刺入罐底，搅之无块为妙。次将上好硝三钱打小块投下，约十分之三。再次将白硼砂三钱打碎投下，亦十分之三，少顷再投入生矾，逐渐投下，候烊尽。照前投硝、硼少许，如是逐渐投完，直待浦起罐口，发如馒头样，方可加起炭火，烧至干枯。然后用净瓦一大张，覆罐口一时取起，将牛黄少许为细末，用清水五六匙调和，以匙超滴丹上，将罐仍入火内烘干，即取起，连罐覆洁净地上，先以纸衬地，罐上仍用碗覆之，过七日，收贮听用。须轻松无监纹者佳，如有监纹者不堪用，或留作蜜调用，亦好算敷药。时初起火宜缓，然亦不可太缓，恐致矾僵，定难溶化，后必监实有纹，中间及后，须用武火，又加矾末烊尽，即投硝、硼，必不能全化，以致坚实有纹矣。须用倾过之旧罐，取其入炉不爆碎也，如用新罐先将炭烘过，然后入炉，亦不可放湿炭上烘，使湿气入罐，经火必碎。又说倾银过之罐，恐犹有毒瓦斯。此丹宜制备，愈久愈妙。
须烧茅柴者，谓之百草霜。取其近底者，锅心及锅口边，俱不可用。先刮去浮面一层，后刮去中一层，不可重刮，盖着锅第三层，又不堪用。
Method for Preparing Alum and Nitre. Also known as Jade Elixir (Yudan) or Snow Frost (Xueshuang). First, take one qian of raw alum (Mineral: Alumen), crush it into pieces the size of beans, place it in a silver crucible, put the crucible into the furnace, and melt it using charcoal fire. It is ideal if no lumps remain when pierced with chopsticks and stirred. Next, add three qian of high-quality nitre (Saltpeter), broken into small pieces, about three-tenths of the total amount at a time. Then, add three qian of white borax (Borax), crushed, also about three-tenths. After a short while, add more raw alum gradually until completely melted. Repeat adding small amounts of nitre and borax as before, continuing until all ingredients are added. Wait until the mixture rises above the rim of the crucible, swelling like a steamed bun, then increase the charcoal fire intensity and burn until dry. Thereafter, cover the crucible mouth with a large piece of clean tile, let it sit for an hour, then remove it. Take a small amount of real musk (Moschus), grind it into fine powder, mix with five or six spoons of clear water, and drip this mixture onto the elixir using a spoon. Return the crucible to the fire to dry thoroughly, then remove it. Place the crucible upside down on a clean surface lined with paper first, and cover the top of the inverted crucible with a bowl. Leave it for seven days, then store for future use. The product should be light and free of cracks; those with cracks are unsuitable, though they may be kept for mixing with honey or used as topical applications. When initially heating, the fire should be gentle, but not too slow, lest the alum becomes stiff and difficult to dissolve, resulting in solidification with cracks later. In the middle and later stages, strong fire (Wu Huo) must be used. If alum powder is fully melted before adding nitre and borax, they will not fully dissolve, leading to hardness and cracking. Use old crucibles that have been previously poured out from, to prevent them from bursting in the furnace. If using new crucibles, pre-heat them with charcoal before placing them in the furnace; do not place them on wet charcoal to dry, as moisture entering the crucible will cause it to crack upon heating. Some say crucibles previously used for melting silver may still contain toxic fumes. This elixir is best prepared in advance; the longer it ages, the better.
Those made by burning thatch are called Baicaoshuang (Hundred Herbs Frost). Take the soot from near the bottom of the pot; neither the center nor the edges of the pot mouth should be used. First, scrape off the top floating layer, then scrape off the middle layer. Do not scrape repeatedly, as the third layer adhering to the pot is also unsuitable.