Yes you can still use our cone 06 glaze on top of a fired pottery piece that used highfire glaze. It can be tricky and may take practice, but you can paint our glow glaze on top of your fired pottery. After you apply the glaze you can use hairspray to try and seal it in so it wont rub off so easy.
We recommend the translucent glow glaze so you can still see what is underneath the bit of glow while still having a semi gloss finish.
Of course you can also do this process to any piece that has been lowfire glazed but not fired yet.