I sold a rental house on land contract several years ago and last year (and probably the years after I sold it) I entered it on my schedule E and deducted depreciation and listed the principal payment and interest as all rent. Now I have no depreciation (it is all used up) and only have the principal payment and rent to record. I now know I should have used a form 6252 and form 4952. What should I do? I think I paid more taxes because I counted all the payments as rent instead of principal. Can I now start using the correct forms? Last year the income was about $5,000 and depreciation $1,000. Please advise. Thanks.