Colorado Affidavit for Sales Tax Exemption for Farm Equipment (DR 0511). Colorado has no permanent farm exemption number: each vendor keeps a signed DR 0511 on file and may ask for a new one at least every two years. Send it here and a renewal reminder is set for each vendor.
The signed copy's purchaser part is used for every vendor. Each copy sent is dated the day it is sent.
Dealer and email are required to send. The vendor gets the signed DR 0511 as a PDF, dated today, from office@m77ag.com. A reminder goes on your to-do list 30 days before the two years are up.
A photo of the signature on white paper works; the background is made transparent before it is saved.