Best course of action for this rust?

[copestake]

Whilst underneath my car I noticed the rubbery undercoat coming away and after pulling some off I've been met with this..



I've took a wire wheel to it to see how bad it is.





No the car isn't worth much so I'm not sure what the best course of action is? Thinking just waxoyl over it?

[copestake]

It's just not worth welding new plates in for how much the car is worth. Not too worried about making it look like it was before just as long as I can slow down the process.