Hello Irene
Some people do find that as base/tops coats are used more regularly and therefore the liquid is exposed to the air more as the brush is moved in and out of the bottle and the top left unscrewed, then they may get thicker a little quicker. Please find our guidance for storing our products below, and hopefully that will help you.
Always keep your Nailberry colours, base and top coats in a dry, cool environment, such as a fridge. Do not store in extremely high temperature or in direct sunlight. We also recommend against applying nail polish in the sun, as this can cause the formulation to thicken very quickly.
We also advise cleaning the neck of your Nailberry bottle after each use with a lint-free cotton pad (so it does not stick on it), then closing the lid tightly after use.
If you continue to have an issue, or have any other questions then please contact us on nailberry@nailberry.co.uk.
Kind regards
The Nailberry Team