Comma Usage

Explanation
The comma connects two independent clauses joined by a coordinating conjunction. This is a correct comma usage.

Explanation
These commas separate items of a list (in this case they separate nouns). If it is appropriate to say "and" between the items in the list, then a comma is acceptable.

Explanation
Commas offset only NONESSENTIAL appositives. In this case, the knowledge that the books are damaged is crucial to understanding which box they go in. Thus, this appositive is essential, and no commas are necessary.

Explanation
This appositive is nonessential. The fact that Andrew Jackson was a US President is entirely unrelated to his breakfast preferences, and therefore, the commas are fitting.

Explanation
Commas do not separate independent clauses. Semicolons can join two independent clauses, but when a comma is used as it is above, the result is known as a comma splice. Comma splices are not professional or proper, but they are hard to notice. If you really want to connect these sentences with a comma, you must use a coordinating conjunction to link the clauses.