Matched context for burn off and purge

The page lists matched contexts for burn off and purge.

Share - burn off	Share - purge	Phrase
9.88%	9.87%	{burn off or purge} vapor [perform operation]
2.96%	3.07%	{burn off or purge} gas [perform operation]
7.84%	0.46%	{burn off or purge} co [perform operation]
4.22%	0.24%	{burn off or purge} modal will