With a Grande, it will take a long time to clear up, but it can be done.
The fastest way I know of is you turn the lamp on until it is about to release the first amount of wax up the globe. Once it gets close to that point. Turn it off and leave it off for about 3 or 4 hours. Then repeat the process.
This is how I cleared my Grande. It took nearly a year to get it nicely clear, but it is worth it.