...Use lots of soap and water!

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If you have a dirty DIPSTICK where the oil has literally baked on and you can not read it easily as was the case on my '86GT, here is a helpful quick hint that takes less then 5 minutes to do.
1. Remove the dipstick.
2. Clean off the engine oil with a rag.
3. Spray "EASY OFF Oven Cleaner" down the entire length of the dipstick.
4. Allow to eat at the residue for about 1 minute to eat the burnt on oil
5. Wipe off with a clean rag.
6. Repeat if necessary in severly stained areas.
7. Replace your dipstick
That baby will shine there after! 
Now about the other DIPSTICK you may have to contend with...Sorry, that is another thread. 
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