I very rarely write discs now, but this is what I use to do depending on the type of coaster:
Successfully written, but with a mistake, e.g. boot CD that won't boot:
I test their durability.
Pop one in a bright window, another on the shed roof, one facing up, another down, etc. After a week, I test their readability compared to when freshly written.
The results: Pretty much every disc left outdoors over a week or two in the Irish weather is rendered completely useless, often to a state where I would not dare load it, i.e. usually partially, if not completely transparent with the surface flaking away. For the discs left in a sunny Window during the summer, they tend to go a much deeper colour, first developing bad sectors and then becoming unrecognisable (like no disc loaded) after a week or two.
[B]Failed the write process or which fails verification[/b]
This time throwing them like a Frisbee, striking them on various surfaces to test scratchability, running over them with my wheelie chair, flexing them, etc.
One that I can say is that it is surprising how robust some discs are compared to others. In the early days of CD-R, it was extremely easy to scratch the top coating along with the recordable layer off and a slight flex would shatter the disc. Then there are others that are very durable and can be flexed in a complete U shape before breaking. I haven't tried the microwave yet.