Polysorbate 20 is a solubilizer, meaning it can help emulsify small amounts of fragrances or essential oils into water. It has the potential to make clear solutions, but I've found that isn't often the case. You could try using more polysorbate 20 in your products - say a 2:1 or 3:1 ratio. This ratio will vary with the different types of essential or fragrance oils you use. Keep really great records about each and every fragrance or essential oil ratio you discover, including the name of the company from whom you purchased them as these things can vary from vendor to vendor.
Please use weighted measurements when making products as it's much more accurate. You are likely not using 1 part essential oil to 1 part polysorbate 20 as 1 tsp of each won't be the same. 5 ml of essential oil will weigh about 4-ish grams, while 5 ml of polysorbate 20 could weigh 6-ish grams. That's a big difference!
If you aren't getting the clear product you want, consider a few things...
1. Try putting it into an opaque bottle. I know this seems a little obvious, but it really is the easiest way to fix this. Out of sight, out of mind.
2. Consider another solubilizer. I've done some experiments with different ones...
My experiments with PEG-40 hydrogenated castor oil resulted in some lovely clear solutions with black amber lavender & Clementine cupcake fragrance oil (part one) and Yuzu fragrance oil and peppermint essential oil (part two).
The bubbly tops in this picture are thanks to vigorous shaking! They don't stay that way.
My experiments with caprylyl/capryl glucoside didn't go well as I couldn't get a single one to solubilize and not float to the top of the test tube. I have also found this solubilizer incredibly sticky, so sticky that the drop that dripped down the side of the bottle took some of the wooden benchtop with it when I tried to lift it up! I don't recommend this one as it's just so sticky on your skin!
Cromollient SCE is a really nice solubilizer that can be used at up to 3%. It makes really lovely, clear, moisturizing solutions.
Caprol Micro Express also creates clear solutions and acts as an emollient, too! A simple solution is to use 1% fragrance or essential oil with up to 10% Caprol Micro Express. Mix well, then add to 0.5% liquid Germall Plus and 88.5% distilled water!
Funnily enough, I've just written my monthly column for Handmade magazine on this very topic! I'll post a link to it when it comes out!
So the short answer is to use weighted measurements to experiment with how much polysorbate 20 you need to work with the essential oil of your choice. The longer answer is that you may never produce a clear solution, so consider another solubilizer.