You must have seen this type of glass everywhere from Zara Home to boutique Hotels.
Of course, most of it is factory produced and the DIY method only mimics the technology. However, there is nobody to judge! This type of glass looks lovely in dimmed light, especially if the light is coming throughout the glass. It is a great easy fix for unloved glass items.
So if you have a couple of old boring bottles/votive/candles/jars etc - try this!
1. Take off or cover up the caps, lids or any other bits you don't want to spray.
2. Start by wetting the surface. Use a plant spray to create mist that would collect into water drops, but if you don't have one, just pat the glass to create water drop 'stains'.
3. The next step must be quick! Spray your preferred colour (ideally something a little see-through, like metallic or washed out colours) onto the surface. As the paint will stick to the glass, the drops of water will not let it dry. Leave the bottle to dry for 15 minutes, depending on how fast spray dries.
Don't worry if some of the water pools or runs down, it shouldn't make a difference to the pattern.
When you think the paint on the glass is dry, test it by lightly running a paper towel down the side of the bottle to collect water with paint. If the paint does not move or scratch - continue to pat the water drops dry. As you continue patting, the irregular drops will become more apparent creating the "mercury" effect.
Depending on how see through your paint was, consider giving the whole surface a second layer of very thin spray all over. Don't worry, you will see the 'drops' coming through with the light coming through the glass. I have left mine with one coat, just because the paint was opaque and would most likely cover the pattern up completely.
You can also create this effect on the inside if you have enough room to spray!
For the end result, you should be left with something like this...