Most household and construction debris is fine. The facilities that take Twin Falls loads set the main limits.
Southern Idaho Solid Waste, which runs the transfer station and landfill, won't accept certain items at any of its sites. The list includes regulated hazardous waste, PCBs found in old transformers and light ballasts, bulk liquids, radioactive material, explosives and ammunition, and electric vehicle batteries.
Hazardous waste, paint, solvents, fuel, and asbestos don't belong in a standard dumpster either. Residents can take many of those items to the district's household hazardous waste program at the transfer station instead. According to the City's hazardous waste page, it takes up to five gallons of antifreeze or used motor oil per visit, not to exceed 25 gallons a month. The program is meant for households, not businesses.
Refrigerators can also go to the transfer station, where a small fee covers removing the refrigerant. Mention any appliances when you book.
If you're unsure about anything, check with your account manager before you load it.