Passenger window on 30 5 window coupe

[Tveditr]

When I bought this car it had a cracked passenger window. Finally getting around to replacing it. Looks like a simple job if I could get the glass out of the channel it sits in on the bottom. The fabric and rubber material that holds it in has turned into a hard brittle material. It won’t let go of the glass. I put some dishwashing soap in the channel to soften it and lubricate but it still won’t let go. Any tricks or tips would be appreciated.