If your Galkyd Gel mixed with Cold Wax medium is dried, it is best to throw it away. I have tried to resurrect it and if it is still pliable, you could add a bit of
gamsol and try and smooth it out. However, if it is so dry that it is quite lumpy, the best thing to do it just make a new batch.
One way to try and prevent your Galkyd Gel and cold wax medium from drying out is to add a drops of gamsol over the mixture inside your tin. That way, it will help prevent evaporation within the closed tin.