Hi, has anybody used Windsor and Newton's All Purpose Varnish for a charcoal and soft pastel drawing?

I just finished a charcoal and soft pastel drawing and want to protect it permanently. All i could find at the local Michael's store was Windsor and Newton All Purpose Matt Varnish. It doesn't say specifically it can be used for charcoal, but it's all purpose. Is it ok for charcoal and soft pastel? Thanks!