I do what you do. Because I use Feline Pine, I wait till the pellets turn into sawdust (cleaning out the poos everyday) then I dump it into a "Flexforce" trash bag (that's a whole other story) and take it to the dumpster.

I use the FF bags because one time I carrying a bag full of litter to the trash, when the cheap bag I was using burst, covering my stairs with icky litter, poos, etc.

I clean out my boxes with Nok-Out, an enzyme cleaner that is safe for all animals. Also gets the smell out of the plastic of the box. I replace my litterboxes every couple of years.