Any ideas of how to get ballpoint pen off a bumbo seat?

[Pinewood]

My DS decided to treat his sister's lilac bumbo to an artist session with a ballpoint pen and I cannot get it off. Does anyone have any ideas what sort of cleaning solutions you can use on this type of plastic? Thanks

i'm sure ours came off with just normal household cleaning spray and a wipe with a microfibre cloth, perhaps you have more sticky staining ballpoint pens then us?

white spirit (shouldn;t dissolve i tbut test on the base first)

Thanks guys for the tips. I tried the household cleaning stuff (Cillit Bang)and it didn't shift I was sure it was ballpoint pens but you have now made me think & I am really hoping that he didn't get one of my hubby's CD writing pens (they are usually well hidden!) as they are permanent ink - yikes! I will have a go with the white spirit when I get back from work