I disagree. While you might be able to use them, to use them effectively is going to require some training and experimentation.
One night in the self-defense class I teach at the studio, I took in a box full of stuff that can be used for weapons. Included were pens/markers, a hairbrush, a book, a couple of bottles, some magazines, a couple of bandanas, a sock, a golf ball...etc.
My basic format was that everyone would grab something out of the box and proceed to come up with as many ways to use it as possible with no prompting/coaching from me (this was done "in the air"). After a couple of minutes, I'd have them switch to something else. We continued this until everyone had a chance to play with every item. Once everyone had used every item, we ran a technique line and, once again grabbed random items to defend against a simple attack (we just worked against a basic grab or punch since the point of the exercise was to use the weapon, not to worry about what attack was coming).
It was interesting because a few people were able to use all the items pretty effectively right from the begining (primarily those who were either advanced students, or who had a lot of experience using weapons). Others were not as imaginative/creative and had to be given a few tips.
My point is that some people will be able to grab anything and "go to town," others will have to train a little. Improvised weapons are just that, improvised. If you don't know how to use the weapon, for which you are substituting something else, you probably won't fare very well with that "something else."
