Question Author
Thanks guys,
dotty, I too have seen when they have cleaned a picture (or part of) on the antiques roadshow, and think also it was mainly for oils. Looked up on a website for cleaning pictures and it mentioned using a slice of bread for oils as a most effective way!!
cherryelm, have no idea if the picture was sealed, (it was bought in St Ives - coastal town famous for artists painting the landscape - many years ago). Didn't want to do the wrong thing and try cleaning with any solution, without first checking that it was safe to do so. Will now take it to a local art shop and ask for their professional help/opinion.
Thanks for your replies, most grateful xxx