How to clean handles:
Dip a cotton swab in ammonia-anise solution. Anise tincture will do.

Then, using a dampened stick, go over all the dirty areas of the handles and, if necessary, other parts of the stove.

Leave it for a few minutes and you will see the fat melt right before your eyes.

Where there is dirt left, clean it with a toothbrush.

Now your hands will shine with cleanliness!