try diesel it penetrates better didnt ever free up a cable on your bike when a kid ? platsicine is sort of playdough , but today i think its been classed as unsafe .
find something like it if you can , at the top of outer cable when its hanging (from a door,gutter, a tall slow moving kid ) make a little cup type thing out of t , mould it to the outer cable so penetrene wd diesel crc wil soak into the inner of it , then just ease it slowly sometimes or most times it will free up work it untill its nice and free keep it lubed .
soak for as long as it takes , most times it has worked
