GIMP2 editing a drawing photo

[Steve Campbell]

Hi all
Wondering if I can get help here. My son drew this picture in art at school and got an award for it. He's very proud of it !

To save time, the teacher photocopied the squared paper that they used instead of asking them to draw it in pencil so it could be rubbed out afterwards. I'd like to "tidy up" the squares "invisibly" and then print out and frame his drawing.

Can anyone describe simply how to do this in GIMP2 ?

Ideally I don't want to lose the "clarity" of his drawing by getting too "blurred". Would be good for me to learn a little how to do this on GIMP anyway.

Any help please ? or pointers to the correct help ?

Thanks

[Steve Campbell]

Managed to figure it out !

[Vintage Racer]

Nice job..............both drawing and editing!