Frame I have dug out the back of the shed for road build up has a plastic cupped BB I am trying to remove.

The proper tool was just mashing the spline things (old 6 dimple campag type), went on to try;
pipe grips – not enough hold
drift and hammer – mess
chain whip – almost, then shredded

waiting to get to work again to use vice and the big molegrips, but think this is just going to lead to more shredded plastic

so, ideas?

Melt them out?
I take it you’re going to replace the bottom bracket anyway…

did think melt, but the only thing to hand is blowtorch or welder which seems overkill to the frame

maybe cut off flanges/ends somehow and hammer the cartridge through

the bb is going, rattly old tat

Have you got the old BB out?
If you have what about an old screwdriver from the opposite side and lightly tap it to break it up?

EDIT Just reread you original post, both sides have a plastic cup?

both sides have plasic cups, it’s just like a regular cartridge, but with plastic cups

it’s in the boot of the car until I go into work next week now