Haven't tried the other one...the problem with that one is that there's a small hole on the back were the motherboard is exposed...I don't know if water got in there...I don't know if I should open it now...
I hold it slot below and shaked...I felt something fall out of the slot and into my leg...then the game (Fire Emblem Fates) could enter the slot and click...No idea if I have anymore rice grains in there...
Next time remember if you remove battery for too long or the battery doesn't get charged after is drained completly for too long the time must be reset.
I didn't charge my 3DS for the past 6 months, it's probably depleted for too long, I'm probably good to buy a new battery too. (not sure if it lose charge capacity to let it too much drained)