I've seen glass shops use soapy water to make the stainless slide in easier, but the best and safest way is to remove the glass and weatherstrip, keep the w/strip attached to the glass, insert the stainless into the slots in the w/strip, reinstall the entire assembly into the car. I broke the last NOS tinted windshield because I tried to force the stainless into the slots while the windshield was still in the car.