Hi took a radiator off to decorate room and when put back on noticed the top nut opposite the drain plug was stained so I undid this and also the drain plug hex nut which had an old black washer on they both came off very easy for a slight woman like me but now worried should I have taken them off do I replace them ? will they leak can i buy washers don't know what to do with them bit worried has they are not mentioned in my little DIY book,help please. 
