To fill a scented sachet, cut the top part off an empty 2 litre plastic drinks bottle. Fold electrical tape or similar over the edges to prevent any cuts. Place a small elastic band (you can just make out a green band in the picture) on the bottle lid before placing in the hole in the fabric that you have left for filling, then pull the elastic over your fabric to hold it in place while you fill.
I just made this hop and lavender scented sachet for my husband. I'm hoping it's scent will soothe him to sleep sweetly tonight! He's had a busy week!