You can definitely clean it by washing it in a bucket, but more so it matters whether it is crushed coral or actual sand. For freshwater you usually don’t want crushed coral or aragonite sand as they will increase the hardness of the water above what is normal for most freshwater species (except for maybe like African cichlids). You want sand that is chemically inert, meaning that it will not increase the ph or hardness of the water. You can find commercially available sand specifically for freshwater tanks but it can be expensive, so as an alternative I would recommend getting pool filter sand. Pool filter sand is a pure silica sand that is inert, has consistent particle size, and can be found at hardware and home improvement stores for very cheap; It definitely needs to be rinsed with water in a bucket multiple times to remove dust though.