1, the 4B eraser will be relatively clean.
2, HB pencil, H is the abbreviation of Hardness, which stands for "hard" degree, B is the abbreviation of Black, which stands for "black" degree. HB stands for a pencil with half of the "hard" and "black" degrees.
3, the difference between pencils is mainly in the ratio of toner to clay, from hard to soft in order of 4H 3H 2H 1H HB 1B 2B 3B 4B but the harder the color, the lighter the color, the smaller the hardness, the darker the color.
4, 4B eraser can erase all 4B pencils, 4B pencil is darker than HB pencil, can be cleaned by 4B eraser, then 2B is cleaner.