Examine the specimen contained within the cassette. Note any tissue ink, cut surfaces, lumen, or layers that may be present. Even if you recognize the specimen type, use an electronic or paper-based accession log, embedding worksheet, or gross description to verify the tissue type, number of pieces, or other important information you will need to know to orient the specimen correctly. Next, you will select a base mold of an appropriate size that will hold the specimen and still allow for a border of paraffin to remain around the edge. It is also helpful to keep the tissue type and microtomy protocols to be used in mind when selecting the appropriately sized base mold.