If the brass is very pitted underneath it may not ever be nice again. If it is not too bad then it could come to look like new.
I have had a number of razors replated with Chris Evatt at razorplate.com. He is a true gentleman of the old sort and is the best replater I have encountered! You need to ship it to the US though. Cost of plating as I recall starts with USD 55 for a full razor in bright nickel (absolutely gorgeous) and upwards from there in other platings. If you're interested you can send a few pics to Chris and ask him to evaluate. As we speak I have 3 Aristocrats homebound from him - good times!
However - for a HD, unless this one has sentimental value, you can find another great condition specimen for the same price. I happen to know one for sale right now at another site for 40 EUR or so, in superb condition, shipped out of the Netherlands. NB - not me selling, but a guy I know and trust.
Best of luck!