I'm not sure if you use Facebook at all but Marketplace is where I've seen the cheapest incubators locally, at least where I am.View attachment 3560497 That is a score. I've been watching CL and there's not really been anything cheap in my area but then I get to the bottom where it shows other areas and there's always a bargain or two it seems.
Maybe wrap both ports then stab a hole on one side?
Idk but I'm thinking the biggest thing about the plug may be to slow down evaporation