i also am repairing rather than replacing. my windows are about 80yrs young. and some are in better shape than others it seems that the south side takes the blunt of the damage. what i have been doing is mixing linseed oil and mineral spirits and soaking the stripped and sanded remains. i did this because the wood had dried out a bit. i think this is working well, although i have not finished any of them yet. it takes time and patients. i would welcome any tips you would have on the subject. also i have questions about should i use sash rope again or copper chain and what needs to be done if i change to chain.