Not sure if I'm jumping the gun on the translation thing, but I think "leaving leftovers" may be more appropriate than "having leftovers" in the context of the rice gods saying. That is, if Mamiya means that she is offended by the girls not clearing their plate.
Is there a reason Mamiya has tw0-tone hair? She looks like a Mamiya/Irako fusion.
I presume this is made digitally, but it kind of looks like some sort of bleed through the paper. The right side of the whole 4koma looks more pale and blue-tinted than the left.
I'd need to re-check against the printed volumes, but it might be something to separate the online and paper versions of the strip, as the colour wash seems to be present in other ones too.
Okaaaayunforgivable!!Reward?Within every grain of rice resides seven gods!!Leaving food uneaten is totally...As punishment, all of you, wash the dishes!!
Dishes = (お皿)/(o)sara/ in Japanese, thus the washing of Sara.