There are a few ways to get the clearest effect when making your snow globe.
Use distilled or filtered water. The best way to ensure your snow globe is clear is to use bottled water, but if that’s not an option, you can just as easily make it yourself by boiling tap water and letting it cool again. Distilled and filtered water will also help you avoid any unwanted contaminants that may get in the way of a perfect view.
Use store-bought water, which is usually distilled and has been filtered. This will give you the best results for creating a clear globe.
A cheaper alternative is bottled water that hasn’t been treated with minerals or carbonation—you can buy this at most grocery stores.
If you’re making your own distilled water, it’s important to remember that it can take several hours to cool down. If you want your snow globe to be clear as soon as possible, try adding a couple of drops of rubbing alcohol while waiting for the water to cool. The alcohol will help prevent any mold growth once in place inside your snow globe.