Commonly I advise students with 1’s and 2’s who are applying to the most competitive colleges to omit these scores on their applications. The admission officials may assume that the student took the tests, especially if they know for sure that the high school requires it (some do; some don’t). But if the scores are already as bad as what the admission folks might imagine, then it probably makes sense to say nothing and keep them guessing.
Occasionally, high school students get saddled with a really awful AP teacher … one who is so bad that all of the students in the class do poorly on the exam. If that’s the case in your school, you should discuss it with the guidance counselor. He or she might mention on your recommendation that a low AP score was epidemic due to poor teaching. However, this information should only come from the counselor. If it comes from you, it’s likely to seem more whiny than helpful.