Above level 20 Wilderness, you will lose your clue scroll (or casket!), and it will disappear, if it is not among your protected items. Similar to other untradeable items, they are meant to turn into coins; however, as they have a value of zero, they simply disappear. When doing a hard clue involving a Zamorak wizard encounter, this is easy to avoid, as you only need 3 items: a weapon (slashing if you need to cut a web), the clue scroll, and spade. If you bring more than 3/4 items and are attacked by a PKer, you should quickly drop items that you don't care about compared to the clue scroll (such as the spade).
Zamorak wizards are substantially weaker than Saradomin wizards. Zamorak wizards are not poisonous, have low health, low defence (except against Magic), and attack exclusively with Magic (using Flames of Zamorak). As such, activating Protect from Magic completely negates their damage. Since they have very little Defence, melee and Ranged are both effective in dispatching them. If you use Ranged, it is advisable to use a Crystal bow or Toxic blowpipe as they require no carried ammunition that would protect over the clue scroll. Magic, even a Trident, is not advised as they are resistant due to their high Magic level.
Item Quantity Rarity GE market price Bones 1 Always 65
Item Quantity Rarity GE market price Air battlestaff 1 Uncommon 9,062 Earth battlestaff 1 Uncommon 9,061 Fire battlestaff 1 Uncommon 9,064 Water battlestaff 1 Uncommon 9,082 Zamorak monk bottom 1 Uncommon 1,783 Zamorak monk top 1 Uncommon 784
Item Quantity Rarity GE market price Air rune 60; 189; 192 Common 300–960 Earth rune 79; 86; 107 Common 395–535 Fire rune 51; 180; 189 Common 255–945 Water rune 86; 107; 146 Common 430–730 Blood rune 8 Uncommon 2,136 Cosmic rune 25 Uncommon 3,000 Death rune 45 Uncommon 10,305 Law rune 9 Uncommon 1,881 Nature rune 12; 28 Uncommon 2,460–5,740