heat is the answer- also make absolutely sure you have the Proper tool to remove the screws!! Whether they be slotted, socket head, or torx drive. If they are socket or torx I would opt for a brand new tool. Worn tool will get you a rounded out head and then you are really in deep s%^t! As far as the grade of thread sealant, different manufactures use different colors to identify the strength of the product. There is no industry standard so who knows what you have. If you have access to a drill press try chucking the tool and securing the scope in a vise aligned under the chuck. Turning the chuck by hand should provide more than enough torque to do the job. good luck and BE CAREFUL!!