How to clean terrarium??

[Heady]

I've been thinking it might be cool to start a little 10 gallon terrarium to have some kind of mudskippers or something, with crabs etc and maybe just a couple fish in the water part.

This is really just in the idea stage right now, but I was wondering how you clean the gravel in this kind of aquarium?

You obviously can't gravel-vac it, since half of it is out of the water. Any ideas, other than just scooping it all out and rinsing once a month?

[Fishouttawater]

Good question but I keep hearing that mudskippers are very territorial and with a small tank size there should be only a few animals in the tank with it. I have a 15 gal. so ill probably try 1 mudskipper for just starting.