6gen won't start after it has been sitting for a month Options

[gts4]

2.2l, 5sfe. Battery has yellow and blue corrosion or build up. Almost looks like dry foam. I used booster cables with a new car and tried a battery pack. I could get the interior lights on, but when I try cranking the engine I get nothing.

Ideas?

I've had the starter, alternator, and distributor all changed within the last year at different times. Could it be the fuel pump? I recently added my own gas with a canister right before I grounded it. Lastly, could I flood the engine by trying to turn it over too often when nothing happens? How can I diagnose this? Should I clean the battery terminals and try again? Should I change the battery altogether?

I'm thinking of keeping this in my collection instead of selling. So before I replace the fenders, doors, and hatch I'd like to make sure she's running perfectly. Thanks.

[Roadrash]

when you say "nothing" do you mean absolutely nothing? you turn the key and nothing at all? or does the engine crank but not fire? or is there a clicking sound? do the dash lights and door dinger go out? Sounds like a battery to me, with the info provided. Take the cables off and clean them and the battery posts with some baking soda and water and a brush. Once your positive the cables have connection to the battery either jump it or put a battery charger on it at 2v until its charged. That's the first step

[gts4]

Tried again after some cleaning. I cleaned the battery and pan but still need to clean the terminals that hang loose leading to the battery. I wanted to remove them out of the car before cleaning them. I tried again today, and got 1 crank sound, then a weak sound as if power is low. I believe it very likely may be the battery at this point. The door chime sound fades and almost dies at a lower frequency when I put past acc and try and start it. This sound was while it was jumped, but the other car was not revved because I was the only person there. Can I charge the battery myself? Should I get a junkyard battery to swap it out with?

when you say "nothing" do you mean absolutely nothing? you turn the key and nothing at all? or does the engine crank but not fire? or is there a clicking sound? do the dash lights and door dinger go out? Sounds like a battery to me, with the info provided. Take the cables off and clean them and the battery posts with some baking soda and water and a brush. Once your positive the cables have connection to the battery either jump it or put a battery charger on it at 2v until its charged. That's the first step