Baking soda mixed with water can simply dissolve old grease, like the brown grease on this kitchen extractor grille:
This photo was taken after I had sprayed the baking soda solution onto the grille, which is why it has the drops on it. I put a lot of the solution on there. In this photo I had already removed the range hood grille and put it on the floor of the bathroom, because I forgot to take a photo before removing it. If I did this job again, I would not do it in the bathroom, because the old grease actually got on to the bathroom floor. I would do it outside on concrete or something like that.
The grille was removed from here:
For some reason our kitchen has an industrial fan for the hood. It's a little noisy so I might replace that.
This is the bottle of baking soda spray I used:
This bottle says it's from Daiso, but I actually made the solution myself using baking soda I bought in a kilogram bag from D2. I mix 80 grams of baking soda with two litres of water in a two litre plastic bottle. Any more than 80 grams doesn't seem to completely dissolve.
After a short while, the grease can be wiped off with a sponge or brush. In the following photo I've just started to wipe it off.
Here a fair amount of the grease has gone, just from lightly brushing with an old washing-up brush:
It takes just a little more wiping and brush work, together with reapplication of the spray, to get it all off. Here is the finished grille.
The brown colour is a reflection of the bathroom walls, which are wood-effect plastic. Here it is back in place in the range. It's covered with a protective screen which also catches some oil in the extracted air.
Because the grille was so greasy, I used an old sponge and an old brush to wipe the grease off. They were completely wrecked after this so I threw them away.
The sponge and brush are also 100 yen shop ones.