The religious leaders of Jesus' time were more interested in exterior than interior cleanness. Likewise, today we are more interested in baths, showers, dry cleaners, dishwashers, washing machines, mouthwashes, shampoos, toothpastes, dental floss, disinfectants, clean air, clean water, street cleaners, etc. than we are interested in the interior cleaning from our sins by means of repentance, Confession, prayer, and penance.
We have things backwards, for interior cleanness is much more important than exterior cleanness. Without interior cleanness, we will lose perspective on reality (Mt 23:23-24), gradually go spiritually blind (see 2 Cor 4:4), be enslaved (Jn 8:34), and become spiritually paralyzed (see Mk 2:3, 5). Unless we let the Lord cleanse us interiorly, we will apostatize (see 2 Thes 2:3), deprive ourselves of the saving value of Jesus' death (1 Cor 1:17), "surely die" in our sins (Jn 8:21, 24), and go to hell forever.
The Lord has provided for us "a fountain to purify from sin and uncleanness" (Zec 13:1). Go to Confession as soon as possible and pray: "A clean heart create for me, O God" (Ps 51:12). "Thoroughly wash me from my guilt and of my sin cleanse me" (51:4).