Hello. I have an old Kohler kitchen sink. my house was built in 1920 so not sure if it is origional or if it was installed at a later time. the sink is one bowl with double drain boards. right in the middle of the sink around the drain the enamel is washing off and reveling the cast iron. it is starting to rust and I try to keep it dry when not using the sink. every time I wash the sink I can see the enamel wash off in that spot. also the strainer is cracked and will no longer hold water in the sink. the drain opening is 6" in diameter. is there a way to restore the enamel or am I just going to have to baby the sink to keep it from rusting more. also do they still make the old strainers. right now I use a rubber drain plug to keep water in the sink. tried to upload a picture but it keeps saying that it is an invalad type even though it is JPG and only 112KB. Thanks.