I restored my old, porous Lego Technic cables from the 90s. It went easier than I thought. A thin wire and a little skill with the soldering iron is enough : r/lego
LEGO® Power Functions Extension Wire 20” 8871 | Other | Buy online at the Official LEGO® Shop US
Alte LEGO Sets aufbereiten: Anleitung für Reinigung und Reparatur
Amazon.com: LEGO Power Functions Extension Wire 8†8886 : Toys & Games
1 x Lego Technic Electric Kabel schwarz 46 Noppen Anschluss Verbindung Verlängerung Eisenbahn Strom Elektrik ca. 35 cm geprüft Typ I 5306bc046 | Steinpalast EN
Replace LEGO 9V Electric Wire - YouTube
Electric, Wire with Brick 2 x 2 x 2/3 Pair, 20 Studs Long : Part 5306bc020 | BrickLink