On the BIIIIIIIIGGGGG one our factory used to run they would run it until the slats were too degraded to use any more, then pull everything out, a small walk behind digger to clean out the sludge. It had two 8 metre or longer beds.
I treat my slats like consumables. Use them up till no longer useful then replace. They’re cheap.
The table itself gets an air chisel to areas that need to be broken up. Cleaning the table is a crummy job. I do mine about once a year.