What passages in Harper Lee's To Kill a Mockingbird show how Burris Ewell is "othered"?

While it is true that Burris Ewell is "othered" in Harper Lee's To Kill a Mockingbird, meaning treated like a social outcast, it is also true that he and his family members draw such social rejections to themselves because they behave like social outsiders, meaning that they act contrary to the ways accepted by society.

One way in which they behave like social outsiders is by rejecting the notion of bathing regularly, which is very unhealthy. In Chapter 3, Miss Caroline, Scout's first-grade teacher, notices that Burris has hair lice, and Scout narrates that "he was the filthiest human [she] had ever seen." But, more importantly, when Miss Caroline instructs him on how to get rid of his hair lice and tells him to bathe before he returns to school, Burris rejects her instructions and even "laughed rudely."

Another way in which the Ewells behave as social outsiders is by refusing to be educated. All Ewells show up for school on the first day of the year just to get the "truant lady" off of their cases, who "threatens 'em with the sheriff" if they don't attend the first day of school but then gives up on enforcing the law. The Ewells refuse to be educated because they refuse to see the value of education, but they would see the value if they wanted to be contributing members of society.

Anytime a character notices any of the above characteristics of Burris or the rest of the Ewells we can consider that character as treating Burris like an "other," but not without deserved cause. For example, when Burris begins showing his temper in class, Little Chuck Little treats Burris as an "other" by pointing out his temper is not to be trusted, as we see when he gives the following warning to Miss Caroline:

Let him go, ma'am ... He's a mean one, a hard-down mean one. He's liable to start somethin', and there's some little folks here. (Ch. 3)

It can also be said Atticus treats Burris, along with the rest of the Ewells, as an "other" by pointing out that not a single Ewell in multiple generations has ever worked, as Scout explains in her following narration:

Atticus said the Ewells had been the disgrace of Maycomb for three generations. None of them had done an honest day's work in his recollection. (Ch. 3)

According to Scout, Atticus even further "others" the Ewells by saying that they live "like animals"; yet, all of these comments about the Ewells arise because the Ewells behave like social outsiders and not like contributing members of society.