We've had our dual chimneys inspected by 2 companies, and it appears that both have holes in the smoke chambers. One company wants to reline both flues with stainless steel linings and install top sealing damper systems. The estimate for this and a new crown is $4,000. The 2nd company wants to do the same thing more or less, but the estimate is $10,000. We're not sure what it takes to make the chimneys safe, and whether we just perhaps aim to go gas/ventless. Any advice would be welcome, including whether it is safe to use the chimneys before they are repaired. Thanks!