Like all things in life in this Mac 68K world, the machines are going to need a goo-removing wash down and a recapping, including some of the screens. Most of the major caps are at the PSU section of the board but there are a couple of leaky caps to deal with about the logic board and screen. The screen is the hardest to do, so you might have to ask for help with it but if you want to tackle it yourself, there are threads on the forum covering all three recapping subjects.

Plus the PSU itself should be recapped too.