I would start by educating yourself by reading the care sheets specific its breed.
Most tortoise owners soak their torts regularly which would help old skin slough off.
It should also be noted that The Tortoise Table isn't sulcata specific, so even though they say fruit can be fed sparingly, I wouldn't feed fruit except on maybe a monthly basis as a treat
Celery as per thetortoiseeable.org : Celery leaves contain high levels of oxalates, and the seeds have diuretic properties. The whole plant has a high carbohydrate content, a high sodium content, and the calcium/phosphorous ratio is also not ideal for tortoises, so although it is not toxic as...
Take out the tomato and celery for sure, peppers are more of a treat I think (someone chime in here.) The lettuce isn't dangerous but may not be very nutritious (make sure its not iceburg lettuce.) Grass is good tho.