At the Adelaide Xmas Mini this year, everyone was saying how hard it was to find lids for the tint tubes. ive been out looking myself and because of the odd size its virtually impossible. However while i was in cheap as chips today i found these Greenseas Ocean Deli tuna cups with plastic lids. They are almost a perfect fit and i think with a little silicone they will work well. Not sure of the regular price but i managed to pick them up on markdown for only 30 cents..... not bad i think, you get a lid for a tint tube and tuna!!