Sand paper is a good way to clean it. You'll also need flux for soldering, the liquid acid in a bottle and a little brush or corner of a rag works well for this.
I'd use copper or brass for the patch, cleaned the same way.
For heat if you haven't soldered anything like this I wouldn't recommend the torch. Instead a large electric soldering iron will make for an easier job. It's all about cleanliness and heat management. Too much heat is a very easy mistake to make. Use just enough for the solder to flow and only a tad more, anything further is counter productive.
