Cleaning integral straw of milkshake beaker

[Hoopsadazy]

So, how, how, how???

Have tried soaking it for some time but it still looks like there is some stuff in there - only dried milkshake I would guess as is not black or anything. Not had it too long as was Xmas pressie. DS loves it so don't want to ditch just yet.

Your suggestions please!

I use a cotton bud on our sports bottles and pour boilin water down them. I guess it depends on how long the straw is?

Soak in milton at least then it will not be a health hazard

it's one of those straws that winds around the outside, so quite long, and too narrow for a cotton bud :(

Thought about the milton, but I know it is unlikely to get rid of whatever I can see in there.

Pipecleaners.