There is not a straightforward answer for this question.
For small amounts of leftover latex paint, you can allow it to dry in the can and then put the can in the trash. Oil based paint and paint remover should not be placed in the trash.
Pesticides, insecticides, herbicides (weed killer), and fertilizers are also considered hazardous wastes and should not be placed in your general trash. These substances can still potentially get washed into our waterways from the landfill so it is best to take them to a hazardous waste collection facility for proper disposal.