Cache issues driving me insane

I have been trying to customize our fckstyles.xml file. I am aware that my cache needs to be refreshed. I am deleting all private data, closing the browser, then re-opening. My changes, in this case, to the fckstyles.xml file are not showing up. I've repeated that process with four different browsers, IE, FF, Opera, Safari, all the same problem. It's not until the next day that my changes will show up. I'm thinking this could be an issue with some kind of cache on my host's end. I'm waiting for a response back from them. Could this be the problem? Is there something else I can try?