Why oh why don't I bring my wooden furniture inside for winter?!

[FurbysMakeSexNoises]

It's all covered in greeny lichen stuff. I've had a go with a wire brush but doesn't get anywhere near clean. I'm not too bothered but wouldn't want green stuff on my clothes and it makes a crappy first impression.

I don't really want to spend loads of time on this as I am lazy and would rather be tending my veg patch.

Any cunning tips for things to splash on it to make a quick improvement for the summer?

Borrow a pressure washer.

power wash should get it off

Pressure washer and then start covering it up over the winter

A wire brush will scratch it. Scrub it with a nylon brush.

Is it varnished, oiled or what?

Pressure washer is the way, it wont take long at all.

once you have finished wait till its dry. Then apply a stain or varnish.

You should get a plastic cover so you can keep them clean and dry, they aren't expensive and will make them last much longer.

Pressure washers are great but needs to be on a low setting or could strip the paint off! They also can remove pointing from old walls so caution is advised.
I personally use ACE which I treat as some kind of magic potion. It's an extremely effective oxegynated bleach which eats the organic bacteria. I would try it neat or in a half hot water solution, and make sure to rinse well while not letting it touch any plants. I use Ace for everything now, from cleaning or unblocking the toilet, removing stains, it's amazing!

Pressure wash and then oil it if it's hardwood. The oiling doesn't take long at all.

I used to scrub ours - algae and bird shit - took ages. Then dh bought his new boys' toy (pressure washer) and did it in a fraction of the time. Plus he put 3 lots of teak oil on it - I only ever put one.

We've had ours many years and never bring it in or cover it up. There are odd days even in winter when I like to sit out.