Can't say I ever took their toys away. Just not sure how that would work. How old are the kiddos?
Here, what worked was - if it was snack time, "Let's clean up so we can have snack". Kids were hungry, toys got picked up without too much of a struggle. Or "Time to go outside" and kids wanted to head out - wasn't too much of a struggle.
I only ever had a few toys out a time. It wasn't a big deal to tidy a few up before moving on to the next thing.
Or we'd have a train day - where they'd have them out all day (might even spill over to the next day) and that was ok, so long as it was relatively tidy. We have set areas where certain things can stay out. Once it got kind of chaotic, then it was time for it to be put away. Incentive was - "Who wants to make set up a fort?"
Could you make a game of it? I worked in a nursery school as a teenager and we always made games of tidy up time. Again, depends on the ages of the kids.
Thinking if you've taken them away - then just like a reward chart - for every time they tidy, they earn a reward? Then they might come to expect rewards though for just doing what should be expected anyhow. Hard one ..
ETA: Saw your SWH. Glad you figured it out :) 6 and 9 .. ok I was thinking much younger
Organization helps too - I agree with Diane. We have big tubs (one for Barbies, one for Beanie Boos, etc.) and they can just pile the stuff in there when their friends leave. Having a 'home' for toys helps.