How to Collect Powder Snow and Other Bucketable Blocks
Bucket Lib supports bucketable blocks, which are blocks that can be picked up directly with a bucket instead of being mined. Powder snow is the classic example.
Find the block
Bucketable blocks are placed in the world like any other block. Powder snow generates naturally in snowy biomes, and other mods can register their own bucketable blocks through the library.
Use the bucket on the block
Right-click the block with an empty bucket. If the block is registered as bucketable, the bucket fills with that block's contents and the block is removed from the world. For powder snow, you end up with a bucket of powder snow that you can carry around.
Place it back
Right-click a block face with the filled bucket to place the bucketable block back down. This is useful for moving powder snow without it melting or for relocating modded bucketable blocks.
Troubleshooting
If right-clicking does nothing, the block is probably not registered as bucketable. Only blocks that a bucket mod has explicitly added support for will respond. Also make sure you are using the correct bucket type, since some bucket mods restrict which blocks each bucket can hold.