What should i spend my coins on?

Almost positive the 20%s expire 24 hours after purchase. I stocked up mostly on 50%s (plan on scrolling a weapon for my Xenon soon) and a few hammers. Annoying side is since the scrolls expire, one per slot.

Just bought one to check and it was perm :f6:

I was going to stock up on some of those but [MENTION=618]Takebacker[/MENTION]; ruined my dreams and said we're going to get 50% +8atk scrolls in some future coin shop.
I'd normally just say pineapple the 20%s at that point but i said that with the 90% hot time ones and we never got those.
Anyone know where they come from?

[MENTION=6790]Green4Ever[/MENTION]; I still have like 10-15 of the gold awakening stamps/carved gold seals from the hot times way back when, i was gonna stock up on those originally but i remembered the stamps/seals i had. I don't like the 50%s hammers because then i need clean slates if they fail.

Edit: decided to clean slate my heart's 2 slots back. 0/24 10%s work. Get annoyed and use the 2 20%s i've had sitting on my kaiser forever