Mastery Tokens

Mastery Tokens give 0.1% of the maximum mastery pool XP to Mastery Pool of the corresponding skill when they are claimed. Mastery Tokens are earned randomly while training a non-combat skill. The drop chance for mastery tokens is 1 in [math]\displaystyle{ \frac{18\,500}{\text{Actions unlocked for skill}} }[/math]. Each thing you unlock by leveling the skill counts as a action e.g. smithing steel platelegs is unlocked at level 40 and counts as one action. Wearing Clue Chasers Insignia increases the drop chance by changing it to 1 in [math]\displaystyle{ \frac{18\,500}{1.1 \times \text{Actions unlocked for skill}} }[/math].

Note that for Fishing specifically, it is more beneficial to wear the Amulet of Fishing instead of the Clue Chasers Insignia. This is due to the Fishing interval reduction provided by the amulet, which increases the number of actions over time, and in turn results in a greater increase in the average number of mastery tokens obtained when compared to the Clue Chasers Insignia. In addition, the Amulet of Fishing also increases the rate at which fish (and therefore XP) is gained.

Mastery Token Chance at Maximum Levels

Skill	Approximate Mastery Token Chance
	Base Game (Level 99)		Throne of the Herald (Level 120)
	Without	With	Without	With
Smithing	1/119	1/109	1/87	1/79
Runecrafting	1/210	1/191	1/133	1/121
Crafting	1/256	1/234	1/162	1/148
Fletching	1/260	1/237	1/186	1/170
Agility	1/342	1/311	1/234	1/213
Herblore	1/513	1/467	1/355	1/323
Cooking	1/544	1/495	1/342	1/311
Farming	1/685	1/623	1/474	1/431
Fishing	1/711	1/647	1/462	1/420
Thieving	1/804	1/731	1/544	1/495
Summoning	1/880	1/801	1/637	1/580
Mining	1/1,423	1/1,294	1/804	1/731
Astrology	1/1,541	1/1,402	1/1,156	1/1,051
Firemaking	1/1,681	1/1,529	1/925	1/841
Woodcutting	1/1,681	1/1,529	1/925	1/841
Archaeology	1/0	1/0	1/0	1/0