UE4 Grime Glass

Hi. I am having trouble adding grime to glass. I manage to get the glass material working, I add in the grime, but when a play you cannot see the grime. Can anyone point me to a decent resource for adding grime or wear and tear to glass please?

Thanks

Are you using an opacity map ?

Are you able to post a pic of your material ?

I have sorted it now. The problem was, I was attempted to add the material with grime onto a plane and it wasn’t showing up. Once I added it to a box it worked. Thank you