Many histologists use forceps and other tools to help them manipulate and position tissue specimens in the desired arrangement. Histologists often have individual preferences for the size and shape of forceps they use. It is recommended that all types of forceps be wiped well between specimens to prevent carry-over contamination from cassette to cassette, also known as "forceps metastasis". The use of forceps without "teeth" or small grooves at the tip will also help in preventing carry-over.
Tissue tampers or stampers can be used to apply pressure evenly on the specimen to help flatten it so that it will harden in one flat plane as the block solidifies. It is essential to make specimens as flat as possible in relation to the block face for a single, representative section of the entire specimen to be obtained. Forceps and other tools used to manipulate tissue during orientation must be kept warm so that tissue fragments do not adhere to tools, as the paraffin on them will begin to solidify on the surface if they are too cool. Small warming wells are found in most embedding units for the purpose of keeping tools at the necessary temperatures. These wells should be cleaned as frequently as any tools used during embedding, as they can harbor small tissue fragments that can then be transferred to adjacent specimens.
