Uncleaned Roman Coins

Anynone ever bought a lot like this one (or maybe exactly one from this trader?)
https://www.ebay.de/itm/Roman-Empire-15-coins-100-authentic/222804237878?hash=item33e02ade36:g:Ws0AAOSwldRaOM0S

I really would like to know if its worth it/ how many of the coins would be in a terrible condition.
And how do you clean them? I have read olive oil is a good method.

I never bought such a lot but I can tell you a few things :
- Most of them will be common nummus, maybe folles, from 4th century, since it represents a huge part of the Roman coins that were ever struck in copper or bronze. Nonetheless, you can still find some good surprises I guess.
- Don't expect too good quality. When a seller grabs a lot of uncleaned coins, he often picks up what he thinks interesting for its good grade and worth solely selling to clean it by himself, and sells what's left in lot such at these. Sometimes a third of the coins in uncleaned lots are not fully identifiable.
- About the question if it's worth or not, it depends on what you want. Some people prefer buying a single pre-cleaned coin for 15$, some people prefer buying uncleaned lot, clean the coins and discover them, even if they know it won't be as good quality as the coin they would have bought for 15$. Two different approaches of collecting roman coins I'd say. If you're more like the second one, such lots are good.
- Coin cleaning could be a nice and funny "hobby", to spend time while doing something interesting and discover coins that have been hidden for centuries.

I'd say the price they are asking is fair. It makes about 1€ a coin including shipping.

Olive oil is a good method to remove the biggest part of the dirt I think. I did it once, it takes time but results are OK, moreover it is easy and cheap. Let the coin about 1 month in the oil. Then you have to do the rest with your hands if you don't want to wait ages. But do not force with your brush or whatever you use, or it will damage the coin.
Here are a few tips : http://romancoin.info/complete_guide_to_uncleaned_ancient_coins.htm

I never bought such a lot but I know people that sell them and have seen them in person many times. These coins come from metal detecting and are found in large lots. After checking the seller it seems they come from Croatia, my home country. They were most likely found around Sisak known as Sescia in Roman times. There was a Roman coin mint located there and lots like this are commonly found.

While it is true that the lot is uncleaned the person selling it already knows the period it belongs to and what it contains, as Choucas said they're most likely 4th century nummus and folles. You have a very small chance of finding something valuable in the lot but you'll most likely end up with common bronze coins, anything silver has been removed from the lot.

The price is about right, just a little higher then what lots like this cost on my local market but that's due to eBay fees. If you wanna start a cheap Roman collection and have the time and patience to clean them go for it.

Ty for your answers, well I do not hope to find gold in it but a sestertius or some coins with nice portaits would be perfect. I think I will buy one lot for now and post the results in the forum if anyone else is interested in this topic :).