Ah yes!! I was painting in a clients conservatory and it was in direct sunlight! Thank you I will give it a go! XIt sounds like you may have accidentally exposed your brush to sunlight/daylight. Do you work near a window?
No, thinner won't work but you could try wrapping the brush in an acetone soaked pad for ten minutes and it may soften and you can loosen it/gently scrape it out with downward strokes of an orange stick x
I did not know that could happen!!! Haha thank you I will try all the tipsI accidentally cured my brush in a conservatory! I couldn't get the brush to soften so I took the brush out from an old regular top coat, cleaned it and that fits the bottle perfect. Wouldn't have been so bad if it wasn't a pretty much brand new bottle!