As of the GSH renewal 2015, Skill Boosting is deleted. Skill Boosting is an action you use for upgrade the Skill Level on Characters Skills.The Skill Boosting parchemin is avalible in some Quests.
Skill Boosting ModesEdit
Skill Boosting is avalible in 2 modes. The first upgrade to 40 but have 20% to broke you skill, the second upgrade to 60 but have 40% to broke your skill.