You have a couple courses of action:

1. If the fuel level is low, you can probably dilute it with fresh fuel and this will probably get you going down the road. This is the quickest/easiest option, but not what I recommend.

2. Drain tank. Add fresh fuel. Considerably better than option 1.

3. Tow vehicle to somewhere you can work on it. Drop tank, drain and have professionally cleaned and inspected. Correct any rust issues. Reinstall, add fresh fuel. Most difficult and expensive option, but the best.

I used to have a Dodge Dart that sat for several years before I finally got around to putting an engine in it. I went with Option 1 at first. After ruining a carburetor and a number of fuel filters, I ended up going with option 3.

Edit: Two560Two, looks like we were typing at the same time.

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Whoever said there's nothing more expensive than a cheap Mercedes never had a cheap Jaguar.

83 300D Turbo with manual conversion, early W126 vented front rotors and H4 headlights 400,xxx miles
08 Suzuki GSX-R600 M4 Slip-on 22,xxx miles
88 Jaguar XJS V12 94,xxx miles. Work in progress.