How can I remove burnt smell from white sauce? I was preparing white sauce from milk. 
I started with boiling one half litres skimmed milk for the above.
The bottom was getting burnt as I was not stirring continuously. 

Finally the white sauce for pasta had the pungent smell of burnt milk.
I have tried adding peeled raw potatoes but no idea if it worked as the burnt milk smell and taste prevailed.
Then, tried adding sugar step by step while stirring...still the smell was persisting.
I have tried increasing garlic and onion but the taste and smell remained.

Please let me know how the burnt smell of milk can be removed in these kind of sauces.
Thank you.
There is nothing you can add or do to your sauce to remove or mask the burnt taste. 

Really. Don't even try. Throw it out and start over, being careful not to burn it this time.

For some foods, there are various tricks you can try for removing the burnt taste, but they all start with removing the burnt bits. With a sauce where you've already thoroughly mixed everything together, that just isn't possible.

A side note: you don't need to boil the milk for white sauce. If you have trouble with remembering to stir the milk while it's heating, just use a method that involves adding cold milk to a hot roux. Of course, in that case you need to remember to not burn the roux, but for Béchamel/white sauce, you're basically barely cooking the fat+flour before you add the milk, so it shouldn't be an issue.