Free Fermenters?!

I recently went to my local donut shop and picked up 5 buckets (3.5-4 gallon I think) with lids. They were used to store things like raspberry filling and maple icing.
I am going to try and scrub and sanitize them to remove the flavor.... Now I know people will say, that it will impart flavor in the beer no matter what you do. But I am going to use that to my advantage, brew a sweet stout in the icing bucket and a raspberry blonde in the raspberry bucket, etc.

Since the buckets are only 3.5 or 4 gallons they will be great for splitting batches and experimenting with additives, ferm times, temperatures etc.

The very best part about it was that they are free, the owner was happy to get rid of them.

Has anyone else tried this strategy?

Haven't personally tried it but you should be fine. I'd clean the buckets with OxyClean Free then sanitize them - but don't scrub as you don't want to scratch the plastic. A soft sponge would be perfect for the job.

I'd be very surprised if the buckets actually imparted any noticeable flavor into the beer.

I have 4 5 gallon icing buckets from the Kroger bakery I have fermented in for years. The fruit flavor may hang around for a batch or two, but like you said if you plan accordingly it'd be like aging in a wine barrel.
The only problems I had was trying to be cheap and brew 5 gallon batches, there's just not enough head space in a 5 gallon bucket.