I designed this small cap (thread diameter: 11mm) in replacement of a vaselin tube, I've uploaded the .f3d file so you can tinker it (check parameters window).

Print Settings

Printer brand:

Creality

Printer:

Ender 3

Rafts:

No

Supports:

Yes

Resolution:

0.1

Infill:

50

Notes:

Print it upside down with supports