How to remove old stains from a vintage mac?

[bluewisteria]

Hoping one of you fabulous people can help me here. I have a beautiful cream vintage mac that has old stains on near the bottom... It can be hand washed which I've done with bio gel and as a whole it has come up very well except the ones at the bottom. I 'could' shorten it to axe stains but loathe to do so.

It can be dry cleaned which I could try too but wondering if anyone has any suggestions before I pay out? It is made from 65% polyester and 35% cotton .