These yellow deposits are calculus /tartar. Needs a professional cleaning by a dentist. Please do not follow any home remedies. It is not advised. Its not an emergency. You can wait.
Next Steps
Please get a professional cleaning and polishing done by a dentist post lock down. Do not try anything at home. It ll cause more harm than good.
Health Tips
Brush twice daily. More than the tooth paste, the method of brushing should be efficient enough to clean all the food debris and plaque that is deposited on your teeth. Also your teeth are not in alignment which makes cleaning more difficult. So please be more cautious and brush well.