Well then
you just have to try the Royal Precision, it is purposely built for the Attraction range and it's so lovely to work with.
Try the soak in clean monomer trick first with your old brush and remember to never use acetone on your brushes to clean them.
If you can't revive your old brush, I strongly suggest you go the Royal Precision.
I don't know about your authorised NSI distributor but mine always has deals where I can buy a new Royal Precision brush and some Attraction powders for a really good price, usually the powders are virtually free the deal is that good.
We must work with a good brush, just like any other profession works with good quality tools, we are no different but there are many techs who try and use a cheapo brush and wonder why their results are not crash hot, don't make this mistake and you will thank yourself forever