When a laundry detergent jug is empty, I rinse it very well, then cut out the bottom to make a large scoop for fertilizer and seed-sprouting mix. The jug's handle makes a great handle for the scoop.
When filling trays of inserts (6-packs) or propagation plug trays with soilless mix, the cut edges of the laundry detergent jugs make a great scraper for evening off, and the sides are good tampers.
An old butcher knife with the edge and tip dulled is good for breaking up peat moss in the bale, or mixing soiless mix.
I suppose a trowel works just as well, but mine are rusty and hard to keep clean. Also, the butcher knife is longer and has a better handle.
Awww, I just like used knives!