Correct way to attach speaker wires... Wait, what!!!

most of food vinegar isn't concentrated enough to work on corrosion and the price is different as well.
the only subject i am good at is math. all other ones had inferior grades or little to no interest including chemistry. 

I agree with some of the above posters - bare wire is the best connection - use deoxit or an equivalent cleaner a couple times a year to avoid oxidation- and clean the input connections as well as the wire -  the connector is a means to an end - its only intention is to connect the speaker wire to the speaker post - I avoid them whenever possible and just ensure I have clean wires and binding posts - a connector cannot improve on a bare wire - it can only minimize oxidation and possibly give you a little more surface area to work with 

Bjg? I thought certain connectors when applied properly "could" improve signal compared to bare wire. Am I wrong? My understanding was that "Banana" plugs for one were invented for testing applications but were soon found to have better connection characteristics because the signal actually traveled on the "skin" of the strands. And when terminated to banana plugs the signal then migrated to the skin of said plug giving you more of an abundance of the original signal "as in the valence ring effect". Whereas the bare wire terminated directly to binding posts did not. Am I wrong? Hee hee , I have been before. And part of the banana plug theorem I've been told does sound illogical. But I've never let a little thing like "LOGIC" stop me anyway!

One thing out there is called Stabilant, buy is straight ,the Stabilant 22 is fine also 
That just gas a 4-1 ratio with very pure 99% isopropyl alcohol. It is the most 
Modern protestant out there .NASA,uses it as well as Many top government agencies. It not only is a form of super conductor but once applied it stays for over 10 years in testing if not moved . A small bottle $50
And enough to do your system . First clean All application with 99% or close Isopropyl alcohol until applicator is clean go over slow several times .
Then apply a thin coat to the surface interconnects one surface and center pin 
Then install . Vacuum tubes sound better Caig sell the tiny applicators to clean inside tube pins .I no longer use caig or anything else. STABILANT is clear and non  greasy. Even bare wire coated will then Not oxidize. 

Banana plugs (or BFA) are a good choice if you want to be able to easily change, amps, cables or speakers. They have a large contact area. 4mm in diameter makes their circumference 12.6mm and they are about 18mm long giving a total area of 227 mm2 = 2.27 cm2. That is equivalent to a square of 1.5x1.5cm. This is much larger than the cross section of any normal speaker cable on the market.

Of course the plugs should be of good quality but I think they are an excellent choice for cables up to about 4mm2. If they are screw fitted or crimp on that is basically the same thing as a bare wire connected to a binding post but of course you introduce an extra connection point where the plug meets the jack.

Is soldering bad? How many other solder joints are there in the signal path? There are plenty of them in amplifiers and in most speaker cabinets. So does one or two more make a significant difference?

Solder that contains lead should be avoided as lead has a rectifying property. Unfortunately lead free solder is terrible to work with, which is the reason they added lead in the first place, but it is to be preferred both for its audio properties and for the environment.

Using bare wire on a binding post is very fiddly so for practical reasons I don't like using unterminated cables. It is however the cheapest way of connecting very thick speaker cables and does not require any extra material such as plugs or spades. As some others have pointed out it also opens up for oxidisation of the exposed strands of the cable and that can cause more detonation of the sound in the long run than using good quality plugs with an air tight fit.

If you want to fiddle about with loose cable strands go right ahead. It probably does not sound any worse than using terminated cables but for me personally it's just too much hassle...