My understanding is that only wet paint is considered hazardous material so you are correct in that you can dry it out and dispose of it in your regular trash. I would leave the lid off of the can when you dispose so if seen it is clear that it is dry paint. You can also buy a paint hardening product from home improvements stores like home depot to add to paint if for instance you have a half a can of wet paint that would be difficult to just let air dry. Another option is to see if your community has a recycling center or some offer specific days where they pick a spot in the community and allow you to drop off hazardous materials such as paint for disposal.
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