Hi Chloe, theres a lovely book called The Little Book of Treasure Baskets published by Featherstone Educacation which is really helpful. Basically we were told on our B23 course don't put anything in that would cause you worry and obviously babies must be very closely supervised but perhaps you could include things like an orange, one of those silver scrubby pan washer things, a clean pine cone, a sponge, crinkly paper tied up in a clean colourful piece of fabric things that couldn't be choked on and things that you and your grandsons mum would be comfortable with. Hope that helps, it is quite nerve -racking at first but the babies and little ones do really enjoy them. They are also a cheap resource which can be easily thrown away and replaced.