i have 2 12 guage wires going to one little clip on my speaker terminal...

How should i put them on there? Is there a better way then soldering them? I tried, but it's so tetius! I got them soldered, but they wouldnt go on the clip wouldn't let the scew (banana type screw) go through so i just took it off.

it's somewhat coated in solder..will this harm it at all?