In general, if the sand bed is not regularly stirred (either by you or sand sifting creatures), it would not be a good idea to stir it.
The reason is, there are anaerobic bacteria deep in your sandbed, that will die if exposed to oxygenated water. Basically, if you stir the sand, you expose them to oxygen (in the tank water), they will die and produce a ton of ammonia.
I keep 10 of these sand sifting crabs
they do the best job of keeping sand bed clean in my 90g
they are very entertaining too if you look from the bottom of your tank
Sand Sifting Crab - Group of 5
there a little over priced but still worth it IMO
Cuc don't eat fish waste, they eat algae or left over food