Can "only" emphasize "can't", "don't", "should", "must", "can"?

1. I only can't sell this furniture and this carpet because they are too big.

2. I only can say, “yes,” I can never say, “no.

3. Only don't lock your door.

4. I only don't know how to do that.

5. I only could play the music for other kids and watch them dance

6. “No, no—I only should have had more time. I want another go.”

7. I only must ask you to excuse the disorder in which you find us.

I found all the examples in Google books.

I think in each case "only" seems to emphasize can, don't, could, should, must, but I'm curious whether it is correct to use "only" to emphasize them like in the examples.