My father-in-law had 3 on his CRs. One was tax related, paid, and was about 10 yrs old on his report. We disputed via the CRA and it was removed. Another was related to his business, 6 yrs old, and unpaid and that was removed via a dispute. The last one stuck but was tax-related and paid and was around 7 yrs old.
I also hear from others here that GWs work to if paid.