Sure you can. There are different types of paint for different surfaces, metal, wood, even concrete. Using the proper paint based on what your painting can help you be certain of things like gloss, coating, and chipping. But it shouldn't hurt your walls.
May need lots of coats to cover up, if you don't like though!!
It will explode.
JK, Marquitta sounds like she knows what she's talking about.
It won't dry and will make a terrible mess.
UK
My friend gave me some wood/metal paint, can I use it on interior walls? If not, what will happen?
