"could clarify" is correct and usable in written English.
You can use it when you are asking someone to explain something or provide more information. For example, "Could you clarify your response?".
If you could clarify, that would be great!
An American official said, however, that Mr. Bremer's selection could clarify the process.
A catchy tune could clarify the details of the E.P.A. water-safety literature, Shankar pointed out.
Nothing, though, could clarify what was going through French minds at the end.
The ruling on Wednesday could clarify whether a case can be brought on those grounds.
Manuel held off on an official announcement until the team could clarify Niese's status.
And Mr. Gore's aides quickly called a news conference so that the vice president could clarify his views.
"I want to be remembered as a philosophical instructor who could clarify questions, and present good ideas clearly," he wrote.
Instead the commission could clarify exactly what insurers can and cannot do to keep suppliers' charges under control.
However, we assumed they could clarify ambiguous results.
Further analysis of arachidonic acid derivates could clarify this objective.
