Is it obligatory to wash the bedding and covers that have become impure with madhiy due to masturbation, and do clothes become impure by this such that prayer in them is not permissible?

One must repent to Allah Almighty for reprehensible acts by associating with righteous people, consistently engaging in supplication and remembrance, and frequently fasting. There is no obligation to purify a ritually impure bedspread unless one intends to pray on it. It is sufficient to wash only the impure spot by pouring water over it. However, if the impurity is hidden and you wish to purify the bedspread, the only way to ensure its purity is to wash the entire bedspread.