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“And then I see the disinfectant, where it knocks it out in a minute - one minute - and is there a way we could do something like that, by injection inside or… almost a cleaning, because you see it gets in the lungs and it does a tremendous job, so it would be interesting to check that, so you don’t have to use medical doctors.”

“Something like that” doesn’t imply that he is directly saying that people should actually be pumping cleaning products straight into themselves, or he would have just said that.
There’s for sure some logic in that I think, and it could be a good idea to look into something along those lines - an injection which utilises similar, but not all of the, ingredients found in cleaning products.

This video does show that he seems far more interested in people utilising sunlight to fight it off though, and as sunlight does help the body produce vitamin D, which among other things can aid the immune system, it does sound a decent idea I think.

It wasn't a sarcastic joke, the president was asking a doctor what was seemingly a dumb question and couldn't defend himself. I am not sure it was truly a dumb question at a conceptual level, but getting lasers to boil said coronavirus sounds more viable than nanobots delivering microdoses of safer disinfectants to problem areas in the lungs.