White vinegar and keep it warm but not boiling. Keep scrubbing it every so often. Be careful of the fumes, they will be strong. Should clean right up.
Sugaring for 45+ years
New Sugarhouse 14'x32'
New to Me Algier 2'x8' wood fired evaporator
2022 added a used RB25 RO Bucket
250 mostly Sugar Maples, 15% Soft Maples. Currently,(110on 3/16" and 125 on Shurflo 4008 vacuum, 15 gravity), (16,000 before being disabled)
1947 Farmall H and Wagon with gathering tank
2012 Kubota with forks to move wood around