You can remove a spell from a scroll

[eriktorbjorn]

>READ POWERFUL SCROLL
The scroll reads "guncho spell: banish the victim to another plane of
existence". The spell seems very long and extremely complicated.

>OPEN POWERFUL SCROLL
The powerful scroll fails to open.

>REZROV POWERFUL SCROLL
The powerful scroll opens. Kind of like swatting a fly with a sledge hammer, if
you ask me.

>DROP GUNCHO SPELL
No spell would help with that!

>THROW GUNCHO SPELL AT GROUND
Thrown.

>READ POWERFUL SCROLL
Nothing useful can be made out on the scroll.

I think the root of the problem is that scrolls are transparent containers with capacity 0. V-OPEN imposes the rules that to be openable, the object has to be a container, and either be a door or have a capacity. A non-door with capacity 0 will fail to open.

V-REZROV, on the other hand, only requires it to be a container.

Both Sorcerer and Spellbreaker check for SCROLLBIT in V-REZROV, so I guess that check should be added here too.

[eriktorbjorn]

Nathan Simpson's bug list also mentions that you can remove spells from your spell book by throwing them. You can't in Sorcerer and Spellbreaker, and it seems to be because there SPELL-F handles the THROW action.