Does anyone know how to shrink a jumper so it still has its shape?

[SunshineCake]

I have one with an acrylic, polyamide, wool and elastane mix. It is 1.5 sizes too big now as was a gift as well as being a nice jumper so would like to try. Has anyone done this and it has worked, even if accidentally ?.

I've only managed with cotton ( about 5- 10%) and wool ( hilarious child size results.)

I'm not sure a mix will do much tbh. Acrylic bags ime so goes the other way!

Google gave me hope then said acrylic won't shrink. I managed to shrink dd lovely sweatshirt from Wales by putting it in the dryer but this one refuses to shrink!