cassette will not eject

Just got an 89 three weeks ago and have been trouble shooting issues since (top latching of course, a/c recharge and now the cassette deck. Like the post below, it clicks and therefore have to change the belt (winter project). But before that, I would like to remove the cassette but it will not eject. Is there a trick here or just pry it open with a screwdriver and try not to crack the plastic cover?

thanks in advance.