In Lieu of Italics

[Grammarholic]

Can I do this when punctuating words, individual letters and numbers (instead of italicizing)? Is this absolutely incorrect and out of the question?
His 'A's look like '8's.

Jis 'b's look like '9's.

There were too many 'whereas's, 'therefore's, 'I don't know's, 'ya know's and 'uh-huh's in his speech.

Thanks.

[Mister Micawber]

Is this absolutely incorrect and out of the question?-- No.
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Native English teacher at Mister Micawber's