Rid, clear, unburden, disabuse, purge are comparable when they mean to set a person or thing free of something that encumbers.
Rid is a rather general term but is likely to refer to concrete or specific matters which are burdensome or pestiferous.
Clear is likely to be used to refer to tangible matters which obstruct progress, clutter an area, or block vision and may be used also in relation to ideas that hinder progress.
Unburden typically implies a freeing of oneself from something taxing or something distressing the mind or spirit, in the latter situation often by confessing, revealing, or frankly discussing.
Disabuse is appropriately chosen to refer to freeing the mind from an erroneous notion or an attitude or feeling making clear straightforward thought difficult.
Purge may refer to cleansing out of or purification from whatever is impure or alien or extrinsic. In political matters it may suggest ruthless elimination.