Seche Restore is one of these nail polish thinners. I got it for a very decent price on amazon and it had great reviews. It comes in a box like this:
Inside of the box is the bottle of nail polish thinner, in a bottle with a screw on cap and a glass dropper.
It is a fairly decent sized bottle which really impressed me when I first opened it. I would recommend keeping this in the original box between uses so that the eye dropper doesn't get lost or broken. Overall I like the packaging, it is nice and it isn't too bulky.
Although I do not have pictures of the process, I can indeed tell you that this does work. It is fairly easy to use. Start with 2-3 drops of the thinner in a nail polish that needs thinning. The packaging directions tell you to roll the bottle. I recommend shaking it as hard as possible. You need the thinner to get mixed really well. Keep adding a little at a time and shaking until you have the desired consistency. I say a little at a time because if you put in too much, it's very hard to fix.
I used this on all of my goopy nail polishes. I used it on a range of brands such as OPI, China Glaze and Sally Hansen. It made one of my 6 year old OPI nail polishes like new. You may run into some trouble if you have glitter saturated polishes that are very goopy. I ran into this problem with another OPI polish.
When you go to use one of the nail polishes that you have thinned out, make sure you shake it well before using it to make sure that everything is mixed up together. You can also add a few more drops later on.
Over all, this is a great product, it really does work. I think every girl that uses nail polish should own this.