I'm replacing my gear oil tomorrow in preparation for my first trip out this weekend and I overlooked ordering replacement washers for my drain and fill screws. I live in a rural area without any marine dealerships. Can anyone tell me what material these washers are made out of? If possible i'd like to be able to run to the hardware store and pick some up. The part number of what i need is 0311598 but i cant find any specs that say what material it is. Motor is a '94 60 HP. Thanks.