Black gunk

[tonka]

After pumping sap on the grounds to clean out the lines of old sap/black gunk from the prior year, it has come to the point where I am getting very little black specks coming with the sap that amount to almost nothing, I took a clean white shirt to use as a filter right under the releaser, even though I'm still getting black specks coming out of the lines with the sap, is the sap good to boil?

[psparr]

Your fine. For those on buckets, you should see the black gunk with wings on them.