What can I do to help Mini Freeze more???

I have a older mini fridge but the freezer is just not getting cold enough, the only thing I need is the freezer, in theory could I fill the whole lower compartment with insulation, such as clothes, in order to make/keep freezer colder… might there be better household materials to make the little freezer that could, get COLDER, and stay COLDER.
SIGNED THE LITTLE FREEZER THAT COULD. …

Is it defrosted?

Maybe it needs a shot of refrigerant.

You don’t want insulation, you want cheap thermal mass. Bricks, water, sand??

Bottles of water in the fridge section will hold the cold.

I suspect this old unit has a slow leak and needs more refrigerant gas. A appliance repairman can add the correct gas.

This might just be confirmation bias…and I am not an engineer:

I used to have a small fridge under a counter in my basement and it never seemed to get cold enough. Somebody remarked to me that it would get colder if I took it out from under the counter so the coil on the back wasn’t in a place that trapped heat. I took it out and set it in a location where the coil got plenty of ventilation. It SEEMED to get significantly colder after I moved it, but I didn’t check it empirically.

YMMV. I may have dreamed it all.

wrong. Due to the insulation in the wall of the refridgerator, the contents matter very very little.

The heat absorbtion rate into the wall of the refridgerator is related to the different in temperature between the outside room and the outside of the wall of the refirdgerator.

The “thermal mass” inside is just going to take longer to warm up … so it will keep it cold if there is a black out, but the OP’s problem is that the heat is not pumped out to begin with.

Due to the effectiveness of the insulation of the refridgerator already, its a diminishing return to try to improve it. Also impossible if refridgerator doesn’t have the hot element only at the back…

Don’t cover any of a refridgerator which has the hot element all over the outside skin …

Don’t fill the space between the hot element and the main body of the refridgerator. thats for a convection current , hot air rising, to flow up… let the heat out…

If you can’t move the refridgerator out of a very closed up space, can you put an upwards vent in ? the vent should be designed to allow the convection current to flow upward… only upward … (no down and up.)