Tie dye -which fabric - tulip dyes

[CyanBird]

Hi all,
my daughter wants to try tie dye and as her bday is next week I’ve bought a selection of tulip one step dyes.
im now looking for plain white cotton items to dye.. H&M have some items that are 60% cotton 40% polyester … are they likely to take the dye?

any other tips welcomed :)

Thanks :)

From googling tulip dyes, it says that it is best for natural fibres, so I'd go for 100% cotton if possible.