Flexible filler solution needee.

[SkinnyKitty99]

A few years back I filled verticle settlement cracks on my walls. Pretty quick I realised I had used the wrong filler as it didn't sand properly and left a shiny raised line where I had put it. I painted over it but was never happy with the result. I now want to paint again and want to get rid of the existing filler and replace it with something less unsightly! Any suggesthow I get the flexible filler off? Or any other solution? (Cannot afford to re-plaster walls)

 

[RandomGrinch]

A carbide multi tool blade to dig out a vee, a first fill of Toupret Fill-flex (fibacryl) and then a finishing filler of your choice?