Feeding them stuff that firms up their droppings is not a good idea because it is totally not natural. It would be like forcing a person to eat stuff that made them have really hard stools- can you imagine how aweful that feel? Their bodies are not meant to deal with a lack of liquids in their diet.
The best way(s) to deal with keeping a clean area:
Get a good quality cage that is as large as possible. A small cage will get dirtier more quickly and you will have to worry about them getting into their droppings (and potentially getting sick) more often. Cheap cages often have lots of annoying nooks and crannies that are hard to clean. A good quality cage has a drawer that opens from the front so you can change the newspapers on the bottom easily. Get one with wheels (you will see why below).
As mentioned above, buy one of plastic desk mats to keep under the cage. You can wipe it down easily and keeps the majority of the nectar and droppings off your carpet.
Attach a sheet or shower curtain to the wall. I find a cloth one works the best. Get two so that you can throw one in the wash when it gets gross. I attached mine using shower curtains.
Buy Poop-Off!!! For lory messes there is no better product! It is non-toxic and removes those droppings really well... Seriously, it is well worth the price.
INVEST IN A PRESSURE WASHER! You don't have to get a fancy one, but I guarantee you that it is worth the $100 or so that you spend on one. When the cage needs a good clean you can roll the cage outside, spray it down with poop-off and then give it a good spray down with no scrubbing required. I would recommend getting some bird-safe disinfectant to use at this stage. Spray it on, let it sit for the required time and then rinse off. Be sure to rinse all the cleaning stuff off really well (no suds left)!
Try to look for plastic toys that you can throw in the dishwasher. You can spot clean a lot of things, but there is nothing like being able give something a quick thorough clean. Be prepared to have to throw away toys that you can't wash when they get covered in poop! That's not to say don't get things that they can chew up, of course!
Lots of luck - lories are WONDERFUL! What kind are you getting?