Why do you feel you need to clean the gravel?
If your water parameters are OK, all the food and detritus in the gravel will be digested by microorganisms, and eventually used by the plants. It would be very hard to clean your gravel without disturbing everything.
To anser your question: I do not clean the gravel in my nano tanks (half gallon, 2.5 gallon, 4 gallon and 6 gallon). I overfeed at the start, to get some mulm in the substrate, and then let the plants and snails take care of the rest. I use plain gravel, no expensive substrate, and after a few months the gravel becomes fertile with all the stuff accumulated there.