Originally Posted by
Al1943
Remove the problem derailleur and soak it in a solvent, mineral spirits, WD40 or similar.
If you do not feel confident about removing it try to clean and loosen the pivots with solvent while working the derailleur back and forth.
You may need to replace the cable and cable housing.
Use the derailleur setup and adjustment instructions found at
Park Tool Co. » Park Tool Co.. Do all of the steps in sequence leaving nothing out.
I will do that for the Alivio derailleur but the 105 is only a week old so I don't think it needs a deep clean at this point.