Sometimes duff caps can damage components further down the circuit (particularly other caps). Sometimes replacing the caps makes everything hunky dory. To replace caps you need equal or better caps (>=voltage, same uf rating), a 60-watt soldering iron, a solder sucker, maybe some desoldering braid, a toothbrush, isopropyl alcohol, and ideally 2% silver 60/40 solder. Often-recommended quality caps are Samxon and (what I use) Rubycon. They should be labeled as Ultra- or just Low-ESR caps. As for soldering irons, lots of people recommend Weller irons, but any 60W soldering station will do. A 2 to 3mm tip and a very pointy tip are all you need. A little pot of tinning & cleaning "grey stuff" is useful sometimes, too.