Set up or adjust machine controls to regulate conditions such as material flow, temperature, or pressure. Monitor material flow or instruments such as temperature or pressure gauges, indicators, or meters to ensure optimal processing conditions. Start agitators, shakers, conveyors, pumps, or centrifuge machines, then turn valves or move controls to admit, drain, separate, filter, clarify, mix, or transfer materials. Examine samples visually or by hand to verify qualities such as clarity, cleanliness, consistency, dryness, and texture. Collect samples of materials or products for laboratory analysis. Maintain logs of instrument readings, test results, and shift production, and send production information to computer databases. Test samples to determine viscosity, acidity, specific gravity, or degree of concentration, using test equipment such as viscometers, pH meters, or hydrometers. Measure or weigh materials to be refined, mixed, transferred, stored, or otherwise processed. Clean or sterilize tanks, screens, inflow pipes, production areas, or equipment, using hoses, brushes, scrapers, or chemical solutions. Inspect machines or equipment for hazards, operating efficiency, malfunctions, wear, or leaks. Dump, pour, or load specified amounts of refined or unrefined materials into equipment or containers for further processing or storage. Connect pipes between vats and processing equipment. Communicate processing instructions to other workers. Remove clogs, defects, or impurities from machines, tanks, conveyors, screens, or other processing equipment. Assemble fittings, valves, bowls, plates, disks, impeller shafts, and other parts to equipment in order to prepare equipment for operation. Install, maintain, or repair hoses, pumps, filters, or screens to maintain processing equipment, using hand tools. Operate machines to process materials in compliance with applicable safety, energy, or environmental regulations.