I made Traditional IRA & Roth IRA contributions in 2016. I exceeded income limits for that year. Both values become basis carryover as of 12/31/2018. What should I do?

Can I leave the contributions at both Traditional IRA and Roth IRA accounts as is or should I take them out from the accounts? Any penalty if I leave them at the accounts as is? I see some other posts mentioned they recharacterized Roth IRA as a nondeductible traditional IRA contribution within a year. Since mine was contributed in 2016, can I still recharacterize both my Traditional IRA contributions and Roth IRA contributions as nondeductible traditional IRA contribution this year? Thanks!