To remove the cost, Cr the Fixed Asset account (with the original cost of the asset) & Dr the Disposals account.
To remove the accumulated depreciation, Dr that account & Cr the Gain or Loss on Disposals account.
Record the cash received by Debiting the Cash account (or Receivables Control account if not paid immediately), & Cr Gain or Loss on Disposals account.
Close off the Gain or Loss on Disposals account by adding up both sides & putting in a balancing figure in the lower side (this goes to the Profit & Loss account). If the Dr(left) side was greater, you have made a loss on disposal. If the Cr(right) side was greater, you have a gain from the disposal.
Detailed records of fixed asset disposals must be kept. This area is fairly complex and best left to your accountant if in doubt.