welcome here! that's first of all.
a few dyeing processes have passed since I posted my first message about problems with Antron and I must admit now I have less of them. I mean, sometimes it happens but not so often as previously. I don't use a hot bath, I use a tap water which is very warm, but not hot (I can even put my hand into it) - I know it's better for a lighter color than darker one, but I didn't need dark one so far, so there is no problem. I've noticed that a good solution for spots problem is, after immersion, to rapidly crumple fabric and keep it under the water for couple of secunds still ruffling. I suppose it's better than putting a flat Antron piece into the water due to the bulges that may occure because of the air that gets itself under the fleece (and may cause uneven dyeing).
this technique is perhaps obvious to more experienced puppeteers so don't laught at me please

but I just experiment with everything by myself and this was a result.
