SELECT IN List Query

I have a table that has a list of skills, ie "HP One", "HP Two"

I need to pass the these skills from my applications search page to a stored procedure, hence I have a snippet of the SP below.

DECLARE @SkillSet NVarChar (200)
SET @SkillSet = '-HP One-,-HP Two-'
SET @SkillSet = Replace(@SkillSet, '-', '''')
SELECT * FROM CPSkillMatrixLevels WHERE SkillMatrixLevelName IN (@SkillSet)

The following sp does not return any results, but when i set the last line to ..

SELECT * FROM CPSkillMatrixLevels WHERE SkillMatrixLevelName IN ('HP One', 'HP Two')

It returns a set of results. Also when I do a select on the variable @SkillSet, ie SELECT @SkillSet, it displays 'HP One', 'HP Two'

Can enybody help me here, i Know i'm doing something wrong, but I cant think of what it is.

Thanks