I picked up a selection of pine cones recently and noticed quite a bit of pitch/resin on them. Does this need to be cleaned off before casting, and if so how have you handled this in the past?
Yea. I don't pick them if they have too much of that sap on them. If it's just a little sap near the outsides, it's no problem. It can be picked off with a knife or trimmed off with the band saw if you need to trim them down to be smaller, which often is the case. I wouldn't leave any sap on the cones. It won't fill with resin, it will just be a gummy soft spot in the blank.