don't know about stopping the blueing, that's caused from running to rich. the cones are supposed to help with some of the backfiring, reverberation type noise.
"I" swear by them,..N they DO help prevent "Blue'n", I've used them on many style pipes,fer many years,...Those a SAMSON "Tru-Duels",..I put
them on in fall of 2000,......No Blue....