What kind of cleaning do you have in mind?
If it's just the usual build up of dirt, you can use a powerhead to blow it out. You can also save a couple of buckets of water from when you do a water change and remove the rock one piece at a time and rinse it off in the removed water. You need not do the entire tank at once, and it's usually better if you only do about 1/3 the tank every week or so.
There are more extreme methods you can do, but I'd only use them if you have a specific problem.