Anyone bought used IBC tanks locally and not regretted it?

Setting up a small bottling trial for liquid fertilizer and I need a couple of intermediate bulk containers for mixing and temporary storage without blowing half my startup budget on brand new tanks that are just going to smell like seaweed extract after the first batch anyway. I keep seeing listings for cleaned second hand units and came across https://www.crateco.ae/products/ibc-tank-1000-litres-used-cleaned while searching last night, the pricing looks reasonable compared to what I’ve been quoted elsewhere in Sharjah industrial area but buying used always makes me a bit twitchy especially when the previous contents are a mystery. Does anyone have experience with these cleaned IBCs from a proper supplier versus the sketchy ones you see stacked outside random warehouses, like do they actually come with some kind of cleaning certificate or is it just a visual scrub and a hose down? I’m not planning on food grade obviously but I don’t want residue from some mystery chemical reacting with my fertilizer and turning my trial run into a foamy disaster. Also curious if the valves on these used units are usually functional or if I should budget for replacing a couple right out of the gate.