Not sure how well known this is, but the most effective thing I have found to burn is torn sinew. You can burn 2 to turn an area pestilent, quickly clear it with no corruptions, and then 6 to max it out for the boss with only 3 corruptions and full rewards. The sinew gain is also net positive, even if you somehow don’t get any during the clear since the max rewards generally give more than 8 sinews.
Add onto this, I’m not sure how consistent the amount is. Some zones will max out at 6, others are 8. Regardless, burning plague materials is a net positive.