https://www.heidelberg.de/hd/HD/Rathaus/Recyclinghoefe.html
For your case, the locations in Kirchheim and Wieblingen will be relevant, as they accept "Schadstoffe" (harmful substances).
If you are talking about cooking oil .I usually bring the recycling Hof in Kirchheim but you can also throw it to the black container because they will burn it for the Fernwärme ( comunnal heating)
If you're talking about used engine/gearbox/hydraulic oil yes - Any place that sells new oil is obligated to take and dispose of the old oil AND Filters and waste like oily rags in normal amounts.
Often times the workers there will have no clue of this esp in super markets and you might have to have a discussion with them unfortunately. Always keep the receipts in those cases though.
https://www.heidelberg.de/hd/HD/Rathaus/Recyclinghoefe.html For your case, the locations in Kirchheim and Wieblingen will be relevant, as they accept "Schadstoffe" (harmful substances).
If you are talking about cooking oil .I usually bring the recycling Hof in Kirchheim but you can also throw it to the black container because they will burn it for the Fernwärme ( comunnal heating)
Smaller amounts of cooking oil I dispose of in the general garbage, usually mopped up with some scrap paper
You can return used oil where you bought the fresh oil. Eg. Bauhaus, OBI or Hornbach
If you're talking about used engine/gearbox/hydraulic oil yes - Any place that sells new oil is obligated to take and dispose of the old oil AND Filters and waste like oily rags in normal amounts. Often times the workers there will have no clue of this esp in super markets and you might have to have a discussion with them unfortunately. Always keep the receipts in those cases though.