Hi spotter, this is very common with sea recovered items. At least you say it was a gift wasn't it?
I restored a few of these and it took about 2 1/2 years, some successful some not.
I contacted the Mary Rose project for advice. Started off by putting in stream for about 4 months, taking out periodicly, cleaning and chipping off raised rust blisters, then returning to stream. next leave to soak in dustbin full of fresh water for few months, occasionally changing water. Then add to last batch of water a 1 to 6 ratio of Sodium hidroxide, found as main ingredient in oven cleaner, can buy a gallon/5ltrs for 10.00 fron wholesaler, enough for 1 dustbin. This chemical is good for removing salts. finaly after few weeks hose off, cleanup with emery clothe, and let dryout slowly in cool place. Slowly warmup over few weeks. (Never use heat) must be patient.worth it in the end. finaly spray with clear laquer.
Hope this is useful to potential restorers.
Cheers Tim.