For separated motor oil (e.g. oil changes), it can go to my local auto parts store, but gasoline and most other car fluids (e.g. coolant, transmission fluid, etc) goes to the dump as hazardous waste. My area does an event once or twice each year to collect all of those hazardous materials, so it’s worth checking that out as well, since it can be way more convenient than waiting in a line at the dump.