Overpass API: How to get key items (not their values)

Hello,

Struggling to do this Overpass query, ready to give up so I ask just in case it is possible! Heads up, I am just a hobbyist starting up so I can follow some code extracts and try to understand them but it's quite hard for me to come up with my own code.

I work on this node for example and I can display the bin and show the name in a box using css. No problem so far...

[out:json];
(
  node["amenity"="recycling"]({{bbox}});
);
out body;
>;
out skel qt;
{{style:
  node[amenity=recycling] {
    icon-image: url('icons/maki/waste-basket-24@2x.png');
    icon-width: 30;
    text:name;
  }
}}

Now, 2nd step, I want replace the name in the box by what kind of recycling it offers (clothes, glass_bottles, paper, etc...).

So I am not interested in the value of these keys but the actual keys themselves. Is there any way to do this using Overpass Turbo?

Any help very much appreciated.

Cheers!