|Scroll by David C Sutherland III from Monster & Treasure Assortment Set One: Levels One-Three (1977)|
"...a Holmes DM could simply allow for re-memorization from scrolls. These could be bundled to create a dungeon-ready magic book (dungeon book). In B2, a blank vellum book costs 20 gp (at the Bank in the Keep). Adding a known spell to the dungeon book requires the same cost/time as constructing a scroll. In a pinch a spell can be cast directly from the book as a scroll, but it then disappears and the magic-user must once again return home to his magic books to learn the spell. Furthermore, due to the cost and time for enchantment, the scroll or dungeon book acts an a mnemonic enhancer and allows memorization after a night's sleep rather than requiring a full day of study."
Here's an example of how this would work. The 1st level M-U, Malchor, has learned and copied six spells into his book of first level spells. He rolled 120 gp for starting money, and purchased about 100 gp worth of equipment (pg 9), leaving him with 20 gp - not enough to make a scroll. His party explores the tunnels under the ruined tower of Zenopus. The fighter Bruno bashes through a door and fights a big goblin while Malchor puts the rest of the goblins to sleep using his single memorized spell. The party finds 500 sp and 2000 cp (90 gp per Holmes) and returns to the surface. They decide he should invest in a scroll, so he prepares a scroll of sleep using the treasure and his personal funds (100 gp + 1 week). The party re-enters the dungeon and has an encounter with a wandering group of large spiders; Malchor puts four of the six to sleep. One spider is felled with arrows; Bruno is poisoned by the other before it is defeated by Mogo the Mighty and Priestess Clarissa. They try to leave the dungeon but cannot get back through the locked doors in a room with a large statue. While looking for a safe room to spend the night, they encounter a group of pirates in a sea cave. Does Malchor use his scroll spell of sleep on them, or save it for re-memorization?
This is why I like the idea of using scrolls as an add-on for re-memorization in Holmes. A new 1st level M-U won't be able re-memorize in the dungeon if he can't afford a scroll. Once he gets 100 gp, he can make a single scroll of his favored spell. He can then bring this to the dungeon, and re-memorize this single spell if a safe resting place is found. Or he can use his scroll as needed, but won't be able to re-memorize after that until he returns home. As he gets more money, he can carry more scrolls and have more versatility in memorization while traveling. The "scroll spell book" becomes part of resource management - there will always be the decision of whether to use that last scroll or not in combat.