Lol, sold them all. It was the only stuff I was comfortable to sell, because unlike Items you will probabaly not need old coins for any quest or weapon/car upgrades. XD
I just noticed I didn't even upgrade my car to fly, even though that excited me so much in the past. O:
Nooooooooooooooooooooooooooooooooo they were the catalyst for extreme amount of EXP lol, it's understandable though. I think I sold a few without me realizing this. I'll post it right now.
1) You need Rare Coins or Debassed coins. You just need roughly 20-25 of them.
2) Then you go to Elemenancy to create an Expericast with a Lv. 90 EXP Bonus by combining any 1 magic (fire, blizzard, or thunder - no need to use 99, just 1 of any will suffice) with amount Rare Coins or 20 debassed coins. You will receive 5x Expericast spells to use. Do this two more times with your remaining coins. You will
not want Firaga/Blizzaga/Thundaga level spells because you will want to use as many spells as possible in a short time without killing a particular beast, so basically 1 fire, 1 blizzard, 1 thunder together, and then 20 of your coins or more in that catalyst spot.
3) Check the Wiz Chocobo Outpost and buy the Fat Chocobo Triple Decker sandwich for a 50% EXP boost. If you haven't unlocked it yet, just do the quests for the Wiz (the local "restaurant owner") until you complete "A Feathery Feast." It costs about 1000+ Gil.
4) Travel to the area just north of the Hammerhead and fight the Lv. 38 Bandersnatch (or Wyverns+Thunder rocs since they are quicker). Unload ALL of your Expericast magic in one battle with him. If the Bandersnatch dies before you can use all your magic, you can get him to respawn by saving at the Hammerhead and reloading your save, then going back to his location (but save beforehand of course). You should be able to hit over 100,000+ EXP. once you've used all your Expericast spells, provided that your 50% EXP boost hasn't worn out. This is the shortest part of this whole ordeal, as you should be able to use all your magic in less than 10min.
5) Go to the hotel of your choice to cash in your EXP multiplier (Galdin/Altissia). Obviously, Altissia will provide the most.
Someone found almost an exact similar idea I hear too, it's where I heard about the 50% EXP. I acquired
600,000+ one time and by the time I went to the hotel I literally hit
1,200,000 EXP.
