In the File LitteringB41_RecipeCode.lua on Line 134

player:getInventory():AddItems("Base.CardboardFlat", 1);

Should be

player:getInventory():AddItems("LitteringB41.CardboardFlat", 1); so that the Cardboard flat is returned when unpacking Jars

Also the line above 133
player:getInventory():AddItems("Base.JarLid", 6);

should either not be there or the recipe for putting Jars in the Cardboard Flat should be changed to include Jar Lids because as it stands now you can pack empty jars and when you unpack them you get Empty Jars + Jar Lids

In the File LitteringB41_VanillaOverride.txt on Line 283

PaperclipBoxEmpty, should be EmptyPaperclipBox, so that one can actually pack the paperclips once you have 40 paperclips and empty paper clip box