Pick them uip on the inventory and drop them off screen so that they all drop into a tiny pile, or, build an incinerator. Youtube minecraft incinerator, I have two in mine, and 2 pools.
Theres a bunch of tutorials but rather than explain it all out in detail it's easier to just watch.
You use a lava block to make a small pool then throw junk in it, either that or make a crap load of storage boxes, I decided I was bored and was gonna build a whole new island and I now wish I hadn't incinerated so much rock and dirt XD
When I say use a lava block, it has to be the SOURCE block, i.e. the block all the lava is flowing from. If you want a WATER source block you can just pick up a bucket of sea water, but if you find a waterfall you HAVE to find the source block or you can't pick it up and it wont flow. Also, be careful when you place it, never open and close doors with a full lava bucket or you might dump the lava down in your house and bone yourself over XD luckily I found that out with a water block