Get up to $20 off your next Castrol Oil Change - depending on the Castrol Oil you choose - Castrol GTX ($7), Costrol GTX High Mileage ($10), Castrol GTX SynBlend ($10), Castrol Tection Extra ($10), Castrol Hypuron ($10), Castrol SLX (20) or Castrol EDGE ($20) - Limit one redemption per person, household or address.  You must use the Official Mail-In Certificate and completely fill it out.  You will be required to provide a Proof of Purchase dated between 5/1/2012 and 12/31/2012 inclusive. 
See www.Castrol.com and choose Promotions for the Official Rebate Form.