Cool Tips in Microsoft Paint!
If you press Ctrl+E a pop-up menu will appear!
Under “Colours/Colors” select “Black and White” instead of the usual Colour/Color.
This:
goes to this:
It might be useful for grayscale comics!
When you hold shift and erase, it replaces the colour 1 with colour 2 wherever you erase so you can fill in with that and than colour it with erasing.