A really inexpensive glass with perfect anti-newton properties is non-glare picture frame glass. This stuff has a subtle but easily seen texture that suggests that it would not work in an enlarger but it does; sort of. I make negative carriers using this glass as the top glass and I leave out a bottom glass. A film negative wants to pop upward when the heat from the enlarger hits it. A top glass prevents this. A bottom glass really has nothing to do except gather dust or perhaps prevent the negative falling into the enlarger bellows.

An enlarger with a strongly collimated illumination system, a condenser or point light design for example, will image the texture of anti-glare picture frame glass. My Durst 138S enlarger certainly does.

A semi-condenser or diffusion system enlarger probably won't image anti-glare glass. My Omega D2V certainly does not. And if I put a diffusing screen into the light path of the Durst 138S it doesn't image anti-glare glass either!

So, beating newton rings is easy and cheap for me but only if I am prepared to accept a significantly diffused light source in my enlarger. So far, so good.