Refillable T273XL Epson Ink Cartridge InstructionsThe T273XL cartridges are very different than standard Epson cartridges and look more like Canon or HP cartridges. There is either yellow tape or a plug at the edge of the cartridge (usually orange) which must be removed before use. This is for an air hole. Air has to get in for ink to get out. If you forget to remove this, it won't print. Wait a few seconds for the pressure to equalize before removing the plastic orange piece on the bottom. It's a good idea to do this over newspaper or over sink because it could leak. Save the orange piece. You'll want to put it back when refilling the cartridge. If you lose it, you can always use a piece of tape and remove it before re-inserting in the printer.
Someone reported that after removing the tape on some T273XL refillables, there was still a glue coating over the air hole, so check to make sure the hole is not obstructed. You can poke a pin in it to make sure.
To refill, do this over a sink or newspaper. Replace the orange piece on the bottom or use tape. Remove the colored plug. Fill the cartridge. Replace the colored plug. Remove the orange piece or tape before re-inserting in the printer.