It sounds like you are trying to use 0.984" tokens which are larger than a quarter. You should have purchased 0.900" tokens which are smaller and would have fit the slots. Or Japanese Pachislo tokens which are often the exact same size as a US quarter.

Of course, it all depends on what coin mechs you have access to. There were some that were designed to accept both US Quarters as well as 984 (they were typically labeled as such).

Depending on the slot/reject button, your only option might be to file them larger to fit the tokens you have. If it is the kind with the slot as part of the black "metal" bezel, then you would need new bezels or convert to a different bezel/button combination. Again, this all depends on which brand of coin door your game has.

Can probably get something that will work from Happ:

http://na.suzohapp.com/amusement_products/coin_doors&C=1&R=All&S=TS

Just open up the coin slots slightly by using a few hack saw blades (two or three sandwiched together so there the same width as the slot. Thirty or so short strokes on the bottom and then do the same to the top of the slot and you should be good. I run .984 tokens at some locations. Quarters at other locations and some locations i use .984-/ quarter combination mechs so the game will take both. You really don't have to open that slot up all that much for a .984...probably only a sixteenth of an inch. That's only a thirty second of an inch on each side of the slot. Kevin