4AGE engine mount inserts

[Vertigo]

so ive got a set of front/back poly engine mount inserts for my adub, and i have a spare set of mounts to practice on before i attempt the real deal. im supposed to be cutting through the rubber and thin steel shell to get the existing mount insert out, apparently it should just slide/pop out when cut through to the outer mount shell, but doesnt want to budge. any tips, or should i just keep forcing it? dont have access to a press, and the instructions say this way is easier!!

[CAMB01]

Try making a few more cuts through it. If not you will require a press.