With the alcohol, do not use 70% rubbing alcohol. You need to use at least 90% isopropyl alcohol. You will generally find it in most pharmacy/drugstores. Be careful not to touch the surface of the heatsink or processor after cleaning as even the oils from you skin can affect the performance of the TIM (thermal interface material). Most prefer Arctic Silver 5 for choice of TIM.
Link to instructions
Arctic Silver Incorporated - Route to Product Instructions for Arctic Silver 5