Suntan wagon folding

Help I have oil painting questions!!? - small timber frame plans

Ok, I have two questions
I have a table that extends over a wooden frame, was suddenly transferred wrinkled (like the wet and dry), how can I rid of it?

The other is that I have only two small oil paintings on eBay when they arrived I realized that the painting itself is somewhat dirty, how can I clean

I do not have much money, so I need cheap options please:)