i've got a tuppa ware dish i'm going 2 use 4 my gecko's moist hide. i wuz just curious if it wud be okay 4 me 2 color the outside walls & top w/black sharpee marker?? if i let it air out awhile b4 i put it in his enclosure & if it's not by ne heat wud that be okay? or is there ne other way i can make the hide so it's dark & not see through???