bottom and top picture stain at silicone joint?

easy way is to scrap out and re apply

for sink and floor can try lemon juice + baking soda (can google this method)

or try Mr Muscle brand marble cleaner (big bottle around rm20)

this marble cleaner very powerful even one of my contractor using this to clean and polish marble but i can't guarantee coz he using machines and maybe different methods

that is clear silicone

same material at vertical joints rite?

u might want to Google for that method reviews and videos

it really works like magic

i lost contact for specialist

Dr. Bath,

any problems regarding toilet he can solve including toilet bowl/long bath crack

u try first if all failed just pm me, i will ask ex colleagues his contact number