PSA: Spend your stars for 8m worth gold before event ends

Star event ends on next maintenance. If you have 250 or more extra stars, buy conversion spell and purification scroll. They are 5m/3m+ worth items respectively. Although the tooltip says they are account bound items, they are converted into tradable scrolls upon use.

Edit: They dont have expiration date once open them. However, extinguisher scrolls are still account bound and also have expiration date.