There’s a nice YouTube channel called Ask A Mortician. She’s a big proponent of expanding the methods of dealing with the departed including composting and “water cremation” (dissolving in acid). Some people get all upset about composting or dissolving “grandma”, and the resulting disposal of the results, but don’t seem to be bothered that blood and other fluids from bodies go down the drain.
During an autopsy, all sorts of tissues may be removed for later analysis and not put back for the funeral. (Fun fact: Mrs. FtG once observed an autopsy. To fill in the space left by the removal of organs kitty litter was used.) These organs and such are later disposed of just like stuff taken from live people during surgery. I.e., a certain class of medical waste.