Sample cans should be cleaned thoroughly before using them again.

• A. True
• B. False
• C. Only if contaminated
• D. Only with water

Answer: (B)

Avoiding cross-contamination between samples is what this question targets. In asphalt testing, the integrity of a sample depends on the equipment not carrying over residues from a previous sample. Many protocols treat sample cans as single-use or as dedicated to one sample, because even thorough cleaning between uses may not remove all residues and can leave carryover that distorts results. Therefore, the preferred practice is not to reuse cans by cleaning; use a fresh, uncontaminated can for each sample. If a procedure does allow reuse, it will require a validated cleaning protocol and verification that no carryover remains.