Explains methods for reducing combined samples to laboratory samples and laboratory samples to sub-samples and general analysis samples, and is applicable to solid recovered fuels that are either: fine and regularly-shaped particulate materials, particle sizes up to about 10 mm that can be sampled using a scoop or pipe, for example: soft and hard pellets; coarse or irregularly-shaped particulate materials, particle sizes up to about 200 mm that can be sampled using a shovel, for example: fluff, chips and chunks; large pieces with nominal top size above 200 mm.