I don't know how it is in other countries. We recently wondered what the right thing to do is and the Citystate of Berlin has an FAQ on recycling: https://www.bsr.de/die-top-13-mullmythen-26874.php which makes some things explicit:
(It is in German, but deepl translated the relevant section)
Do empty bottles and packaging have to be washed out?
No. Because the packaging is rinsed out in the recycling process, when the sorted plastics are shredded. It is only important that all packaging is emptied of residues [ed. The translation misses tmthat they mean large residue or levtover amounts], is not stacked and the lid is removed.
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Sufficient knowledge of German
You must have an adequate command of the German language (level B 1 of the Common European Framework of Reference for Languages).
If you were in possession of either a residence permit or a residence authorisation on 31/12/2004, you only have to demonstrate basic knowledge of the German language (level A 1) to be granted a permanent settlement permit.
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In practice the staff giving interviewing you have leeway to assess your German level on the spot, but applying without demonstrated adequate German levels could lead to wasting ones time.
(It is in German, but deepl translated the relevant section)
Do empty bottles and packaging have to be washed out?
No. Because the packaging is rinsed out in the recycling process, when the sorted plastics are shredded. It is only important that all packaging is emptied of residues [ed. The translation misses tmthat they mean large residue or levtover amounts], is not stacked and the lid is removed.