The first thing you can do is toss the WD-40 in the garbage.
Remove the coin acceptor and install your spare coin acceptor then send the bad one into Parker Engineering and have it rebuilt. Have it made into the EZ model, it’ll come back with a door on the side that you can open to clear a coin jam.
OK it’s an EZ model, then don’t have it converted to an EZ model, send it in for repair.
Here’s a link to their web site http://slugbuster.easystorecreator.com/ call them and a very nice lady will answer the phone and tell you what to do to fix your coin acceptor
Clean the mechanism with rubbing alcohol and q-tips. Throw away the wd-40, it will gum it up. Strip the oil out and clean the mechanism. Make sure that it closes correctly.