I just did go through the review for close queue, and found half of the questions there were valid, and I was even able to answer them(not real good answers, that would have needed a bit more time, but that's not the point), the point is, they are answerable, and therefore valid questions.
Keeping the site clean is great, but keep in mind how a new user feels, if a question gets closed just hours after it got created.
Also, just because the question does not contain enough information to be answerable for you, it can be enough information for someone else to answer. Because sometimes, the topic is just so simple, that there is not needed more.
Example: How to Know that on which channel the coupon has been used in Magento?