Storing Sulfur and Potassium with Blocks
Why Use Storage Blocks
Sulfur and Potassium both have storage blocks: Sulfur Block and Potassium Block. These compress nine-ish stacks of loose material into a compact form so your chests do not overflow after a mining trip. They are storage blocks, not crafting stations, so you do not need to place them to use them.
Compressing Sulfur
Craft Sulfur into Sulfur Block. Do this after a Sulfur Ore or Sulfur Nether Ore run when your inventory is full of Sulfur. Store the Sulfur Block in a chest. When you need loose Sulfur for a recipe, break the Sulfur Block back down into Sulfur.
Compressing Potassium
Process Raw Potassium into Potassium first using a Furnace or Blast Furnace. Then craft Potassium into Potassium Block. Store the Potassium Block. Break it back into Potassium when a recipe calls for the loose item.
Practical Storage Routine
After mining, sort your haul: keep Raw Potassium aside for processing, and compress any Sulfur you are not using immediately into Sulfur Block. Once the Raw Potassium is smelted or blasted into Potassium, compress that into Potassium Block too. This keeps both materials in a compact, stackable form until you need them.